Bug: Slack reaction_added events not delivered to agent sessions

OpenClaw version: 2026.2.19-2
Node.js: v22.22.0
Platform: Ubuntu Linux, Slack Socket Mode
Config: Multi-account Slack setup (6 bot accounts: michael, scribe, nutrition, scout, coder + default)

Summary

Slack reaction_added events are not being received or processed by the gateway. All 6 Slack Socket Mode connections show as connected, regular messages flow fine, but emoji reactions on bot messages in channels produce zero log entries — not even at DEBUG level.

Steps to reproduce

1. Configure multi-account Slack with reactionNotifications: "all" (top-level)
2. Bot posts a message to a channel (e.g. #jobs)
3. User adds an emoji reaction to that message
4. Expected: system event like Slack reaction added: :+1: by user in #channel msg <ts> from <bot>
5. Actual: Nothing. Zero log entries. No session receives the event.

What we checked

• All Slack apps have reaction_added in bot event subscriptions
• All apps have reactions:read scope
• Socket Mode connections confirmed (slack socket mode connected x5 in logs)
• reactionNotifications: "all" at top-level config
• No per-account overrides (inheriting top-level)
• Messages, DMs, threads all work perfectly — only reactions are silent
• Gateway restarted multiple times, config hot-reloaded
• Tested reactions on messages from multiple bot accounts
• Yesterday (same version, same config) reactions WERE working and routing to the channel session correctly

Relevant logs

No reaction_added events appear in DEBUG-level file logs at /tmp/openclaw/openclaw-2026-02-20.log. The word "reaction" only appears in config reload entries, never as an inbound event.

Environment

• 6 Slack bot accounts via Socket Mode
• Bindings route each account to a different agent
• Channel: #jobs (C0AGEJPMKDW)
• groupPolicy: "open" for all accounts

Suspected cause

Possible regression in Socket Mode event handling where reaction_added envelope types are not being acknowledged or processed. The fact that it worked yesterday on the same version and config suggests a transient issue, possibly related to Socket Mode reconnection state.