Sessions/groups inconsistently displayed across mobile app and web (claude.ai/code) vs. desktop app

Environment

• Claude Code desktop app (Windows) — works correctly
• Claude Code mobile app ("Code") — affected
• claude.ai/code (web browser) — also affected

Setup
6 custom sidebar groups, each containing exactly 1 session:
教會服事 / 讀經進度表 / 投資／股市分析 / AI技術維運 / 簡報／視覺設計 / 教會行政

Expected
All 6 sessions and their group assignments should appear consistently across desktop, mobile app, and web.

Actual

• Desktop native app: shows all 6 sessions, correctly grouped. ✅
• Mobile native app: only shows 4 sessions, even after fully force-quitting and reopening the app, and pull-to-refresh. Missing: 【投資】聯友金屬投資追蹤 and 【簡報設計】PowerPoint 評價與評分.
• Web (claude.ai/code): also only shows a subset, and most sessions appear under "Ungrouped" despite having real group assignments visible in the desktop app.

Notable detail
The missing "投資" session was actually the most recently active session of all at the time of testing — ruling out a simple "most-recent-N sessions" cutoff as the cause.

Data integrity itself seems fine (confirmed all 6 sessions still exist via the session list); this looks like a display/sync issue specific to non-desktop-native surfaces.

Happy to attach screenshots if useful.