Correctly handle nested fragment spreads on interface fields (#1735)

Author: enisdenjo

.changeset/lovely-mirrors-hunt.md

@@ -0,0 +1,5 @@
+---
+'@graphql-tools/stitch': patch
+---
+
+Ensure key fields propagate correctly for interface/object combinations

packages/stitch/src/subschemaConfigTransforms/isolateComputedFieldsTransformer.ts

@@ -326,7 +326,7 @@ function filterBaseSubschema(
         }
       }
       const allTypes = [typeName, ...iFacesForType];
-      const isIsolatedFieldName = allTypes.every((implementingTypeName) =>
+      const isIsolatedFieldName = allTypes.some((implementingTypeName) =>
         isIsolatedField(implementingTypeName, fieldName, isolatedSchemaTypes),
       );
       const isKeyFieldName = allTypes.some((implementingTypeName) =>
@@ -360,7 +360,7 @@ function filterBaseSubschema(
         ...iFacesForType,
         ...typesForInterface[typeName],
       ];
-      const isIsolatedFieldName = allTypes.every((implementingTypeName) =>
+      const isIsolatedFieldName = allTypes.some((implementingTypeName) =>
         isIsolatedField(implementingTypeName, fieldName, isolatedSchemaTypes),
       );
       const isKeyFieldName = allTypes.some((implementingTypeName) =>