diff --git a/pages_tool/ai-chat/ai-chat-message.vue b/pages_tool/ai-chat/ai-chat-message.vue
index 2c6e2fc..3ecade6 100644
--- a/pages_tool/ai-chat/ai-chat-message.vue
+++ b/pages_tool/ai-chat/ai-chat-message.vue
@@ -541,7 +541,10 @@ export default {
       // PR-FRONTEND-MEDIA-UPLOAD-FIX (2026-09-16): pendingImages 数组支持 1-9 张图
       //   原 pendingImage 单数对象, 只存第一张, 选 5 张只发 1 张
       //   每项: { localId, tempPath, uploading, uploaded, uploadError, sentWithBatch }
-      _pendingIdSeq: 0,
+      // ⚠️ Vue 2 会过滤掉 _/$ 开头的数据属性, _pendingIdSeq → undefined → ++undefined = NaN
+      //   所有图 localId 都变 NaN, Vue "Duplicate keys" 警告, 数组错乱.
+      //   必须用非下划线前缀. PR-FRONTEND-MEDIA-UPLOAD-FIX-HOTFIX (2026-09-16)
+      pendingIdSeq: 0,
       pendingImages: [],
       scrollTop: 0,
       scrollIntoViewId: null,
@@ -770,7 +773,7 @@ export default {
       const list = Array.isArray(paths) ? paths : (paths ? [paths] : [])
       if (!list.length) return
       list.forEach((path) => {
-        const localId = ++this._pendingIdSeq
+        const localId = ++this.pendingIdSeq
         const pending = {
           localId,
           tempPath: path,