II found a reproducible UI issue related to the Solo and Mute controls.
When I select multiple tracks using Solo and then disable Solo, only the last track that was soloed remains visually highlighted as active. The other tracks remain dimmed, even though Solo is no longer active and all tracks are playing normally.
The issue appears to be purely visual, as playback behavior is correct. However, the UI state does not match the actual track state.
Additionally, the problem persists after saving the project, closing Audacity, and reopening it. The same track remains visually highlighted while the other tracks remain dimmed, despite no Solo state being active.
As a workaround, I can restore the correct visual state by muting and then unmuting the dimmed tracks.
4.0.0-beta.2.261621301 on Windows 11 v 25H2