Bug Description

The Control UI (webchat) renders every assistant response as two identical chat bubbles. This is the same issue reported in #72641, #71785, #72861 — all of which are now locked. The bug still reproduces on my environment.

Environment

• OpenClaw version: 2026.5.20 (npm latest, stable channel)
• Channel: webchat (openclaw-control-ui)
• OS: macOS 26.5 (arm64), Node v25.6.1
• Model: xiaomi/mimo-v2.5 (also tested with zai/glm-5.1)

Evidence

1. Session transcript confirms all message IDs are unique — the server sends each message exactly once
2. Gateway logs (~/Library/Logs/openclaw/gateway.log) show no duplicate sends
3. UI screenshot shows every assistant reply rendered twice with identical content and metadata

Steps to Reproduce

1. Open Control UI (webchat)
2. Send any message to an agent
3. Observe the assistant response appearing twice

Expected Behavior

Each assistant reply should render exactly once.

Notes

Related locked issues: #72641, #71785, #72861. This appears to be a client-side rendering bug that was not fully fixed. Would appreciate a re-open or a fix in a future release.