diff --git a/packages/hydrooj/package.json b/packages/hydrooj/package.json
index 5720e8dfb..ba6f42823 100644
--- a/packages/hydrooj/package.json
+++ b/packages/hydrooj/package.json
@@ -1,6 +1,6 @@
 {
     "name": "hydrooj",
-    "version": "3.1.31",
+    "version": "3.1.32",
     "bin": "bin/hydrooj.js",
     "main": "src/loader",
     "module": "src/loader",
diff --git a/packages/hydrooj/src/model/discussion.ts b/packages/hydrooj/src/model/discussion.ts
index 27589d96f..10945f090 100644
--- a/packages/hydrooj/src/model/discussion.ts
+++ b/packages/hydrooj/src/model/discussion.ts
@@ -250,7 +250,7 @@ export async function getVnode(domainId: string, type: number, id: string, uid?:
     if (type === document.TYPE_PROBLEM) {
         const pdoc = await problem.get(domainId, Number.isSafeInteger(+id) ? +id : id);
         if (!pdoc) throw new DiscussionNodeNotFoundError(id);
-        return { ...pdoc, type, id };
+        return { ...pdoc, type, id: pdoc.docId };
     }
     if ([document.TYPE_CONTEST, document.TYPE_TRAINING, document.TYPE_HOMEWORK].includes(type as any)) {
         const model = type === document.TYPE_TRAINING ? training : contest;
diff --git a/packages/hydrooj/src/upgrade.ts b/packages/hydrooj/src/upgrade.ts
index 859bd5f19..fe67023e9 100644
--- a/packages/hydrooj/src/upgrade.ts
+++ b/packages/hydrooj/src/upgrade.ts
@@ -634,6 +634,20 @@ const scripts: UpgradeScript[] = [
         }
         return true;
     },
+    async function _53_54() {
+        const _FRESH_INSTALL_IGNORE = 1;
+        let ddocs = await db.collection('document').find({ docType: 21, parentType: 10 })
+            .project({ _id: 1, parentId: 1 }).toArray();
+        ddocs = ddocs.filter((i) => Number.isSafeInteger(+i.parentId));
+        if (ddocs.length) {
+            const bulk = db.collection('document').initializeUnorderedBulkOp();
+            for (const ddoc of ddocs) {
+                bulk.find({ _id: ddoc._id }).updateOne({ $set: { parentId: +ddoc.parentId } });
+            }
+            await bulk.execute();
+        }
+        return true;
+    },
 ];
 
 export default scripts;