Joining clip boundaries makes earlier audio disappear

I frequently work with clip boundaries within tracks, to make aligning different tracks easier. I noticed this behaviour which I am sure cannot be intentional?

  1. add stereo and mono track (I have not tried other combinations; it doesn’t seem to occur with just one track)
  2. add audio in both, and some clip boundaries in the mono track, both overlapping with the audio in the stereo track and beyond it (see image 1)
  3. join boundaries at the back of the mono track
  4. audio ahead of earlier clip boundaries disappears without a trace (see image 2)

I use a shortkey to join boundaries, as with the changes to the track labels, just clicking on them to merge doesn’t reliably work anymore. When clicking to join works, the issues does not occur.

I make audio books, so these are hour-long chapters; I use boundaries to align music and sound effects in the stereo track with the voice in the mono. I have had multiple instances where I had to revert half the edits on a completed file just to recover what I lost at the beginning without noticing.

I agree. Definitely looks like a bug.
Which version of Audacity?

3.1.1. I just updated to it tonight, hoping it’d resolve itself, but it hasn#t. It also happened with the previous version.

I’ve logged this bug.
Thanks for reporting.