diff --git a/packages/hydrooj/src/model/user.ts b/packages/hydrooj/src/model/user.ts
index f7b0c3ecc..0b7ecb797 100644
--- a/packages/hydrooj/src/model/user.ts
+++ b/packages/hydrooj/src/model/user.ts
@@ -265,6 +265,11 @@ class UserModel {
         if ($unset && Object.keys($unset).length) op.$unset = $unset;
         if ($push && Object.keys($push).length) op.$push = $push;
         if (op.$set?.loginip) op.$addToSet = { ip: op.$set.loginip };
+        const keys = new Set(Object.values(op).flatMap((i) => Object.keys(i)));
+        if (keys.has('mailLower') || keys.has('unameLower')) {
+            const udoc = await coll.findOne({ _id: uid });
+            deleteUserCache(udoc);
+        }
         const res = await coll.findOneAndUpdate({ _id: uid }, op, { returnDocument: 'after' });
         deleteUserCache(res.value);
         return res;