diff --git a/CHANGELOG.md b/CHANGELOG.md
index 80b9a7e69a..f2ad163081 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,10 +23,15 @@ should change the heading of the (upcoming) version to include a major version b
 ## @rjsf/material-ui
 - Resolve the React error caused by the propagation of the `hideError` property to the DOM element, fixing [#3945](https://github.com/rjsf-team/react-jsonschema-form/issues/3945)
 
+## @rjsf/utils
+
+- Update `sanitizeDataForNewSchema()` to avoid spreading strings and Arrays into the returned value when the old schema is of type `string` or `array` and the new schema is of type `object`. Fixing [#3922](https://github.com/rjsf-team/react-jsonschema-form/issues/3922)
+
 # 5.14.1
 
 ## @rjsf/utils
 
+- Update `sanitizeDataForNewSchema()` to avoid spreading strings and Arrays into the returned value when the old schema is of type `string` or `array` and the new schema is of type `object`. Fixing [#3922](https://github.com/rjsf-team/react-jsonschema-form/issues/3922)
 - update types for `labelValue` to have more granular return types, fixing [#3946](https://github.com/rjsf-team/react-jsonschema-form/issues/3946)
 
 ## Dev / playground
diff --git a/packages/utils/src/schema/sanitizeDataForNewSchema.ts b/packages/utils/src/schema/sanitizeDataForNewSchema.ts
index 2ecba355e2..cd07eea930 100644
--- a/packages/utils/src/schema/sanitizeDataForNewSchema.ts
+++ b/packages/utils/src/schema/sanitizeDataForNewSchema.ts
@@ -137,7 +137,7 @@ export default function sanitizeDataForNewSchema<
     });
 
     newFormData = {
-      ...data,
+      ...(typeof data == 'string' || Array.isArray(data) ? undefined : data),
       ...removeOldSchemaData,
       ...nestedData,
     };
diff --git a/packages/utils/test/schema/sanitizeDataForNewSchemaTest.ts b/packages/utils/test/schema/sanitizeDataForNewSchemaTest.ts
index a6d85d965b..1069ee9780 100644
--- a/packages/utils/test/schema/sanitizeDataForNewSchemaTest.ts
+++ b/packages/utils/test/schema/sanitizeDataForNewSchemaTest.ts
@@ -456,5 +456,32 @@ export default function sanitizeDataForNewSchemaTest(testValidator: TestValidato
       const formData = { foo: '1' };
       expect(schemaUtils.sanitizeDataForNewSchema(newSchema, oldSchema, formData)).toEqual(formData);
     });
+    it('returns empty object when the old schema is of type string and the new contains "property" field', () => {
+      const oldSchema: RJSFSchema = { type: 'string' };
+      const newSchema: RJSFSchema = {
+        properties: {
+          foo: {
+            type: 'string',
+          },
+        },
+      };
+      expect(schemaUtils.sanitizeDataForNewSchema(newSchema, oldSchema, 'qwerty')).toEqual({});
+    });
+    it('returns empty object when the old schema is of type array and the new contains "property" field', () => {
+      const oldSchema: RJSFSchema = {
+        type: 'array',
+        items: {
+          type: 'string',
+        },
+      };
+      const newSchema: RJSFSchema = {
+        properties: {
+          foo: {
+            type: 'string',
+          },
+        },
+      };
+      expect(schemaUtils.sanitizeDataForNewSchema(newSchema, oldSchema, ['qwerty', 'asdfg'])).toEqual({});
+    });
   });
 }