diff --git a/docs/source/1.0/spec/core/http-traits.rst b/docs/source/1.0/spec/core/http-traits.rst
index 23468435747..aab5b3af32c 100644
--- a/docs/source/1.0/spec/core/http-traits.rst
+++ b/docs/source/1.0/spec/core/http-traits.rst
@@ -788,11 +788,10 @@ Trait selector
     .. code-block:: none
 
         structure > member
-        :test(> map > member[id|member=value] > :test(string, collection > member > string))
+        :test(> map > member[id|member=value] > string)
 
     The ``httpPrefixHeaders`` trait can be applied to ``structure`` members
-    that target a ``map`` of ``string``, or a ``map`` of ``list``/``set`` of
-    ``string``.
+    that target a ``map`` of ``string``.
 Value type
     ``string`` value that defines the prefix to prepend to each header field
     name stored in the targeted map member. For example, given a prefix value
diff --git a/smithy-model/src/main/resources/software/amazon/smithy/model/loader/prelude.smithy b/smithy-model/src/main/resources/software/amazon/smithy/model/loader/prelude.smithy
index 356bfa76b59..d7aaea39b34 100644
--- a/smithy-model/src/main/resources/software/amazon/smithy/model/loader/prelude.smithy
+++ b/smithy-model/src/main/resources/software/amazon/smithy/model/loader/prelude.smithy
@@ -610,7 +610,7 @@ string httpHeader
 /// Binds a map of key-value pairs to prefixed HTTP headers.
 @trait(selector: """
         structure > member
-        :test(> map > member[id|member=value] > :test(string, collection > member > string))""",
+        :test(> map > member[id|member=value] > string)""",
         structurallyExclusive: "member",
         conflicts: [httpLabel, httpQuery, httpHeader, httpPayload, httpResponseCode, httpQueryParams])
 @tags(["diff.error.const"])
diff --git a/smithy-openapi/src/test/resources/software/amazon/smithy/openapi/fromsmithy/mappers/prefix-headers.smithy b/smithy-openapi/src/test/resources/software/amazon/smithy/openapi/fromsmithy/mappers/prefix-headers.smithy
index 46968373814..d47b8e39f8c 100644
--- a/smithy-openapi/src/test/resources/software/amazon/smithy/openapi/fromsmithy/mappers/prefix-headers.smithy
+++ b/smithy-openapi/src/test/resources/software/amazon/smithy/openapi/fromsmithy/mappers/prefix-headers.smithy
@@ -24,9 +24,5 @@ structure Output {
 
 map Headers {
     key: String,
-    value: StringList,
-}
-
-list StringList {
-    member: String
+    value: String
 }