diff --git a/packages/runtime/src/enhancements/node/query-utils.ts b/packages/runtime/src/enhancements/node/query-utils.ts
index 00d430696..0effd4557 100644
--- a/packages/runtime/src/enhancements/node/query-utils.ts
+++ b/packages/runtime/src/enhancements/node/query-utils.ts
@@ -225,7 +225,7 @@ export class QueryUtils {
             // model has a discriminator so it can be a polymorphic base,
             // need to find the concrete model
             const concreteModelName = data[modelInfo.discriminator];
-            if (concreteModelName) {
+            if (typeof concreteModelName === 'string' && concreteModelName) {
                 return concreteModelName;
             }
         }
diff --git a/tests/regression/tests/issue-1698.test.ts b/tests/regression/tests/issue-1698.test.ts
index 4d6f52f54..0d9750785 100644
--- a/tests/regression/tests/issue-1698.test.ts
+++ b/tests/regression/tests/issue-1698.test.ts
@@ -1,5 +1,5 @@
 import { loadSchema } from '@zenstackhq/testtools';
-describe('issue 1968', () => {
+describe('issue 1698', () => {
     it('regression', async () => {
         const { enhance } = await loadSchema(
             `