With all tracks muted, after performing a “Mix and render to new track”, the left channel appears muted (in grey) while the right channel appears not muted (in blue). When listening to the track, both channels are truly muted. Why then, is the right channel appearing as if it is not muted? This did not happen before Audacity 3.2.
Yes. Why indeed! As you have already figured out, you can press Mute to bail yourself out.
Trouble ticket created: Half muted track · Issue #4702 · audacity/audacity · GitHub