diff --git a/.changeset/light-mayflies-knock.md b/.changeset/light-mayflies-knock.md
new file mode 100644
index 00000000000..6e13ff7a893
--- /dev/null
+++ b/.changeset/light-mayflies-knock.md
@@ -0,0 +1,5 @@
+---
+"@graphql-tools/delegate": patch
+---
+
+Hotfix: do not use nullable and nonNullable prefixes if field names don't match
diff --git a/packages/delegate/src/OverlappingAliasesTransform.ts b/packages/delegate/src/OverlappingAliasesTransform.ts
index 346eab4103c..b457f47aefe 100644
--- a/packages/delegate/src/OverlappingAliasesTransform.ts
+++ b/packages/delegate/src/OverlappingAliasesTransform.ts
@@ -48,7 +48,7 @@ export class OverlappingAliasesTransform<TContext>
                                 seenNonNullable.add(fieldName);
                                 currentNullable = false;
                               }
-                              if (seenNullable.size && seenNonNullable.size) {
+                              if (seenNullable.has(fieldName) && seenNonNullable.has(fieldName)) {
                                 transformationContext[OverlappingAliases] = true;
                                 return {
                                   ...subSelection,