diff --git a/packages/hydrooj/src/handler/domain.ts b/packages/hydrooj/src/handler/domain.ts
index b36c6711c..9f778e48c 100644
--- a/packages/hydrooj/src/handler/domain.ts
+++ b/packages/hydrooj/src/handler/domain.ts
@@ -326,7 +326,7 @@ class DomainJoinHandler extends Handler {
     async prepare({ domainId }, target: string = domainId) {
         const [ddoc, dudoc] = await Promise.all([
             domain.get(target),
-            domain.collUser.findOne({ domainId, uid: this.user._id }),
+            domain.collUser.findOne({ domainId: target, uid: this.user._id }),
         ]);
         const assignedRole = this.user.hasPriv(PRIV.PRIV_MANAGE_ALL_DOMAIN)
             ? 'root'
diff --git a/packages/ui-default/pages/problem_submit.page.tsx b/packages/ui-default/pages/problem_submit.page.tsx
index 7548af5ab..f429e4edb 100644
--- a/packages/ui-default/pages/problem_submit.page.tsx
+++ b/packages/ui-default/pages/problem_submit.page.tsx
@@ -25,7 +25,9 @@ const page = new NamedPage(['problem_submit', 'contest_detail_problem_submit', '
   }
   for (const key in availableLangs) {
     if (config.langs && !config.langs.filter((i) => i === key || i.startsWith(`${key}.`)).length) continue;
-    if (window.LANGS[key].pretest?.split('.')[0] === preferences[0].split('.')[0]) preferences.push(key);
+    if (typeof window.LANGS[key]?.pretest === 'string' && window.LANGS[key].pretest.split('.')[0] === preferences[0].split('.')[0]) {
+      preferences.push(key);
+    }
   }
 
   renderLanguageSelect(