diff --git a/packages/ra-core/src/form/sanitizeEmptyValues.spec.ts b/packages/ra-core/src/form/sanitizeEmptyValues.spec.ts
index 97f5ec11f12..355d765495f 100644
--- a/packages/ra-core/src/form/sanitizeEmptyValues.spec.ts
+++ b/packages/ra-core/src/form/sanitizeEmptyValues.spec.ts
@@ -45,4 +45,14 @@ describe('sanitizeEmptyValues', () => {
             sanitizeEmptyValues({ obj: { foo: null, foo2: 2 } }, { obj })
         ).toEqual({ obj: { foo: { bar: 1 }, foo2: null } });
     });
+    it("should not ignore initial value when it's not of the same type", () => {
+        const initialValues = { a: 'foobar' };
+        const values = { a: { hello: 'world' } };
+        expect(sanitizeEmptyValues(initialValues, values)).toEqual({
+            a: { hello: 'world' },
+        });
+        expect(sanitizeEmptyValues(values, initialValues)).toEqual({
+            a: 'foobar',
+        });
+    });
 });
diff --git a/packages/ra-core/src/form/sanitizeEmptyValues.ts b/packages/ra-core/src/form/sanitizeEmptyValues.ts
index 8fd1871b8e5..0b54cdb2d05 100644
--- a/packages/ra-core/src/form/sanitizeEmptyValues.ts
+++ b/packages/ra-core/src/form/sanitizeEmptyValues.ts
@@ -20,6 +20,7 @@ const sanitizeEmptyValues = (initialValues: object, values: object) => {
                 acc[key] = values[key];
             } else if (
                 typeof values[key] === 'object' &&
+                typeof initialValues[key] === 'object' &&
                 values[key] !== null
             ) {
                 acc[key] = sanitizeEmptyValues(initialValues[key], values[key]);