Audio being replaced by that of another clip

I've just upgraded to version 16 and I've encountered a mysterious issue that I've never seen before.

I added around 5 clips to a timeline, and after making some basic cuts in the 'Cut' window I noticed that the audio of one of the clips had been replaced (in part) with that of another - along with intermittent choppy moments of silence.

Eventually I ended up removing all clips from the timeline to start fresh. I then added the same clip multiple times to the timeline (let's call this clip A), but as soon as I reached the point in the timeline that corresponded with the original problem its audio was replaced with that of clip B.

Where is this audio coming from? Clip B is no longer part of the video track.

If I mute the video track with the multiple copies of clip A there is no audio at all - on any of the identical clips (which is what you'd expect), but as soon as I un-mute it, the audio from clip B eventually kicks in - somewhere into the third copy of clip A. Note that the waveform of all of the copies of clip A look identical.

Is this a bug, or am I missing something very obvious.

Any help much appreciated.

I've just managed to correct the issue by disabling/enabling the 'conform lock enabled' option on the remaining clips in the timeline. Doing so seemed to remove the mystery audio from the clips that had already been removed from the timeline.

This feels like a bug to me - but I could be doing something wrong.