Fixed for me in Version 2026.10.100, Beta 11 (I don't want to downgrade to check the exact version). It now collapses on my phone exactly the same way it does on my desktop computer. However, the detached banner setting is ignored (edit: I made a separate post for this: https://feedback.fluxer.com/p/4318/community-detached-banner-setting-is-always-ignored).
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Comment by asheline :3