diff --git a/compiler/fir/cones/src/org/jetbrains/kotlin/fir/types/ConeTypes.kt b/compiler/fir/cones/src/org/jetbrains/kotlin/fir/types/ConeTypes.kt
index 186a4f29eef2a..62c15be001667 100644
--- a/compiler/fir/cones/src/org/jetbrains/kotlin/fir/types/ConeTypes.kt
+++ b/compiler/fir/cones/src/org/jetbrains/kotlin/fir/types/ConeTypes.kt
@@ -230,6 +230,9 @@ class ConeIntersectionType(
     override val nullability: ConeNullability
         get() = ConeNullability.NOT_NULL
 
+    val effectiveNullability: ConeNullability
+        get() = intersectedTypes.maxOf { it.nullability }
+
     override val attributes: ConeAttributes = intersectedTypes.foldMap(
         { it.attributes },
         { a, b -> a.intersect(b) }
diff --git a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt
index 3dec0698c661e..d25f762c56a1f 100644
--- a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt
+++ b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt
@@ -182,7 +182,9 @@ fun <T : ConeKotlinType> T.withNullability(
         withoutEnhanced.transformTypesWith { t -> t.withNullability(nullability, typeContext) } ?: withoutEnhanced
     }
 
-    if (this.nullability == nullability && this.attributes == theAttributes) {
+    if (this.nullability == nullability && this.attributes == theAttributes && this !is ConeIntersectionType) {
+        // Note: this is an optimization, but it's not applicable for ConeIntersectionType,
+        // because ConeIntersectionType.nullability is always NOT_NULL, independent on real component nullabilities
         return this
     }
 
@@ -213,7 +215,9 @@ fun <T : ConeKotlinType> T.withNullability(
             }
 
             ConeNullability.UNKNOWN -> this // TODO: is that correct?
-            ConeNullability.NOT_NULL -> this
+            ConeNullability.NOT_NULL -> if (effectiveNullability == ConeNullability.NOT_NULL) this else this.mapTypes {
+                it.withNullability(nullability, typeContext, preserveEnhancedNullability = preserveEnhancedNullability)
+            }
         }
 
         is ConeStubTypeForTypeVariableInSubtyping -> ConeStubTypeForTypeVariableInSubtyping(constructor, nullability)
diff --git a/compiler/testData/diagnostics/tests/inference/genericWithUnmatchedNullabilityDelegate.fir.kt b/compiler/testData/diagnostics/tests/inference/genericWithUnmatchedNullabilityDelegate.fir.kt
deleted file mode 100644
index 61a71782bd602..0000000000000
--- a/compiler/testData/diagnostics/tests/inference/genericWithUnmatchedNullabilityDelegate.fir.kt
+++ /dev/null
@@ -1,12 +0,0 @@
-// ISSUE: KT-67912
-// WITH_STDLIB
-
-interface Bound
-
-inline fun <reified F : Bound> foo(key: String): F? = null
-
-fun main() {
-    val otherValue: Map<String, String> by <!DELEGATE_SPECIAL_FUNCTION_NONE_APPLICABLE!>lazy {
-        foo("") ?: emptyMap()
-    }<!>
-}
diff --git a/compiler/testData/diagnostics/tests/inference/genericWithUnmatchedNullabilityDelegate.kt b/compiler/testData/diagnostics/tests/inference/genericWithUnmatchedNullabilityDelegate.kt
index 6dcb777857cf8..2c70b4ea4eb3b 100644
--- a/compiler/testData/diagnostics/tests/inference/genericWithUnmatchedNullabilityDelegate.kt
+++ b/compiler/testData/diagnostics/tests/inference/genericWithUnmatchedNullabilityDelegate.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // ISSUE: KT-67912
 // WITH_STDLIB
 
diff --git a/compiler/testData/diagnostics/tests/inference/genericsWithUnmatchedNullabilityNested.fir.kt b/compiler/testData/diagnostics/tests/inference/genericsWithUnmatchedNullabilityNested.fir.kt
deleted file mode 100644
index 832e0868dfd2c..0000000000000
--- a/compiler/testData/diagnostics/tests/inference/genericsWithUnmatchedNullabilityNested.fir.kt
+++ /dev/null
@@ -1,12 +0,0 @@
-// ISSUE: KT-67912
-// WITH_STDLIB
-
-interface Bound
-
-inline fun <reified F : Bound> foo(key: String): F? = null
-
-fun main() {
-    val value: Map<String, String> = <!INITIALIZER_TYPE_MISMATCH, NEW_INFERENCE_ERROR!>requireNotNull(
-        foo("")
-    )<!>
-}
diff --git a/compiler/testData/diagnostics/tests/inference/genericsWithUnmatchedNullabilityNested.kt b/compiler/testData/diagnostics/tests/inference/genericsWithUnmatchedNullabilityNested.kt
index a32d720945bcc..7cfa8d6f88d74 100644
--- a/compiler/testData/diagnostics/tests/inference/genericsWithUnmatchedNullabilityNested.kt
+++ b/compiler/testData/diagnostics/tests/inference/genericsWithUnmatchedNullabilityNested.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // ISSUE: KT-67912
 // WITH_STDLIB
 
diff --git a/compiler/tests-spec/testData/diagnostics/notLinked/dfa/pos/11.fir.kt b/compiler/tests-spec/testData/diagnostics/notLinked/dfa/pos/11.fir.kt
index adb39e9541992..1d5e999c2a201 100644
--- a/compiler/tests-spec/testData/diagnostics/notLinked/dfa/pos/11.fir.kt
+++ b/compiler/tests-spec/testData/diagnostics/notLinked/dfa/pos/11.fir.kt
@@ -60,32 +60,32 @@ fun case_3(a: Int?, b: Float?, c: Double?, d: Boolean?) {
         false -> b
         null -> c
     }.apply {
-        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>?")!>this<!>
-        if (this != null) {
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.equals(null)
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.propT
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.propAny
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.propNullableT
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.propNullableAny
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.funT()
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.funAny()
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.funNullableT()
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.funNullableAny()
+        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>
+        if (<!SENSELESS_COMPARISON!>this != null<!>) {
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.equals(null)
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.propT
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.propAny
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.propNullableT
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.propNullableAny
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.funT()
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.funAny()
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.funNullableT()
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>this<!>.funNullableAny()
         }
     }.let {
-        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>?")!>it<!>
-        if (it != null) {
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.equals(null)
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.propT
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.propAny
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.propNullableT
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.propNullableAny
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.funT()
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.funAny()
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.funNullableT()
-            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Nothing>? & kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.funNullableAny()
+        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>
+        if (<!SENSELESS_COMPARISON!>it != null<!>) {
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.equals(null)
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.propT
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.propAny
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.propNullableT
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.propNullableAny
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.funT()
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.funAny()
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.funNullableT()
+            <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number & kotlin.Comparable<kotlin.Nothing>")!>it<!>.funNullableAny()
         }
     }
 }