Cross-session message delivery stopped surfacing in the recipient session — regression in claude-desktop ≥ 1.46388.2

Summary

In the desktop app, sending a message from one Claude Code session to another (the "send to another session" / cross-session messaging feature) stopped being delivered to the recipient as a live turn. The sender's call is accepted, but the message never surfaces or gets processed in the target session.

Environment

• claude-desktop on Linux (Debian/Ubuntu, amd64)
• Affected: 1.46388.2 and 2.110.0. Last known-good: 1.24012.0.

Regression window

Worked fine on 1.24012.0 for weeks. The app auto-upgraded 1.24012.0 → 1.46388.2 (~2026-09-08, per apt/dpkg history) and the feature broke immediately after. Still broken after a later update to 2.110.0.

Symptom by version

• 1.46388.2: the message never appears in the recipient at all — no error, nothing surfaces.
• 2.110.0: the injected message does trigger a turn in the recipient ("waiting for claude…") but it aborts before producing anything; the recipient still never processes the message. The sender's delivery status returns undelivered (no sign of starting within 20s) or queued, but it never lands.

Ruled out

• Forward-updating to the latest (2.110.0) — did not fix it.
• A clean apt purge + reinstall of 2.110.0 — did not fix it (rules out a corrupted install).

Fix / workaround

Downgrading to 1.24012.0 restored it completely — verified with a full round-trip (a message sent to another session surfaces there as a live turn and the recipient replies). Because reverting the code alone fixed it, this is a code regression in the 1.46388.2 → 2.110.0 line, not local config/state.

sudo apt-get install claude-desktop=1.24012.0 && sudo apt-mark hold claude-desktop

Until it's fixed upstream, the stopgap without downgrading is for the recipient session to manually read the sender's transcript.

Impact

Multi-session workflows where sessions message each other are broken on every version ≥ 1.46388.2.

Repro

1. Open two Claude Code sessions in the desktop app.
2. From session A, send a message to session B.
3. On ≥ 1.46388.2, B never surfaces it as a live turn (1.46388.2: nothing; 2.110.0: a turn starts then aborts). On 1.24012.0 the same steps deliver normally.