diff --git a/src/utils.ts b/src/utils.ts
index 326f87c38..e2b29bdd4 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -668,7 +668,7 @@ export function recursivelyAssign<T1 extends T2, T2 extends Record<string, any>>
             continue;
         }
         if ((sourceValue !== null && sourceValue !== undefined) || !ignoreNullish) {
-            target[sourceKey as keyof T1] = sourceValue;
+            safeSet(target, sourceKey, sourceValue);
             continue;
         }
     }