diff --git a/docs/en/operations.md b/docs/en/operations.md
index 50160661..a2dd51c0 100644
--- a/docs/en/operations.md
+++ b/docs/en/operations.md
@@ -48,6 +48,8 @@ reme reindex scope=embedding
 
 `reindex` rebuilds BM25 and/or embedding indexes from the current `file_chunks`. It does not scan the workspace, rechunk files, or rebuild the wikilink graph. Diagnose the watcher first when ingestion is the problem.
 
+`reindex` also keeps whatever chunks are already stored. When the chunking behavior itself changes — an upgraded ReMe or edited chunker settings — the stored chunks are reused as they are, so a plain `reindex` cannot refresh them. Re-chunk from the source files instead by clearing the derived chunk state and letting the watchers rescan; see [Recover derived state](#recover-derived-state). Source files are never modified by this recovery.
+
 Rebuild a daily index page separately:
 
 ```bash
diff --git a/docs/zh/operations.md b/docs/zh/operations.md
index 43e4bcbd..46921c83 100644
--- a/docs/zh/operations.md
+++ b/docs/zh/operations.md
@@ -52,6 +52,8 @@ reme reindex scope=embedding
 
 如果问题发生在文件摄取阶段，应先确认后台 watcher 正常运行；不能把 `reindex` 当成通用“重新扫描”命令。
 
+`reindex` 同样只会复用已存储的分块。当分块行为本身发生变化时——例如升级 ReMe 或修改了 chunker 配置——旧分块会被原样沿用，此时仅执行 `reindex` 无法刷新它们。正确做法是从源文件重新分块：按下文[从派生状态故障恢复](#从派生状态故障恢复)清理派生状态后让 watcher 重新扫描。该恢复过程不会改动源文件。
+
 Daily 索引页可单独重建：
 
 ```bash