diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7915810116..ee9cdca4ce 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ Docs: https://docs.openclaw.ai
 
 ### Fixes
 
+- Mattermost: harden reaction handling by requiring an explicit boolean `remove` flag and routing reaction websocket events to the reaction handler, preventing string `"true"` values from being treated as removes and avoiding double-processing of reaction events as posts. (#18608) Thanks @echo931.
 - Scripts/UI/Windows: fix `pnpm ui:*` spawn `EINVAL` failures by restoring shell-backed launch for `.cmd`/`.bat` runners, narrowing shell usage to launcher types that require it, and rejecting unsafe forwarded shell metacharacters in UI script args. (#18594)
 - Hooks/Session-memory: recover `/new` conversation summaries when session pointers are reset-path or missing `sessionFile`, and consistently prefer the newest `.jsonl.reset.*` transcript candidate for fallback extraction. (#18088)
 - Slack: restrict forwarded-attachment ingestion to explicit shared-message attachments and skip non-Slack forwarded `image_url` fetches, preventing non-forward attachment unfurls from polluting inbound agent context while preserving forwarded message handling.