diff --git a/x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/plugin/ReinitializingSourceProvider.java b/x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/plugin/ReinitializingSourceProvider.java
index a76687f15552a..8dee3478b3b64 100644
--- a/x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/plugin/ReinitializingSourceProvider.java
+++ b/x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/plugin/ReinitializingSourceProvider.java
@@ -15,15 +15,23 @@
 import java.util.function.Supplier;
 
 /**
- * This is a workaround for when compute engine executes concurrently with data partitioning by docid (inter segment parallelization).
+ * This class exists as a workaround for using SourceProvider in the compute engine.
+ * <p>
+ * The main issue is when compute engine executes concurrently with data partitioning by docid (inter segment parallelization).
  * A {@link SourceProvider} can only be used by a single thread and this wrapping source provider ensures that each thread uses
  * its own {@link SourceProvider}.
+ * <p>
+ * Additionally, this source provider protects against going backwards, which the synthetic source provider can't handle.
  */
 final class ReinitializingSourceProvider implements SourceProvider {
 
     private PerThreadSourceProvider perThreadProvider;
     private final Supplier<SourceProvider> sourceProviderFactory;
 
+    // Keeping track of last seen doc and if current doc is before last seen doc then source provider is initialized:
+    // (when source mode is synthetic then _source is read from doc values and doc values don't support going backwards)
+    private int lastSeenDocId;
+
     ReinitializingSourceProvider(Supplier<SourceProvider> sourceProviderFactory) {
         this.sourceProviderFactory = sourceProviderFactory;
     }
@@ -32,10 +40,11 @@ final class ReinitializingSourceProvider implements SourceProvider {
     public Source getSource(LeafReaderContext ctx, int doc) throws IOException {
         var currentThread = Thread.currentThread();
         PerThreadSourceProvider provider = perThreadProvider;
-        if (provider == null || provider.creatingThread != currentThread) {
+        if (provider == null || provider.creatingThread != currentThread || doc < lastSeenDocId) {
             provider = new PerThreadSourceProvider(sourceProviderFactory.get(), currentThread);
             this.perThreadProvider = provider;
         }
+        lastSeenDocId = doc;
         return provider.source.getSource(ctx, doc);
     }