Unexpected behaviour: trimming a region start moves the contents

[Lost_Highway]

I’m editing regions to comp a part together. This has been working fine, but all of a sudden I’ve encountered a problem…

Moving the beginning of regions is moving the contents of the region, so the audio is no longer where it was recorded but moving later and later, the more that I move the start of the region!

Trimming region ends works as expected, with the audio staying where it is, just the end bound of the region moving.

Have I inadvertently triggered a different editing mode with a careless press of a key that’s activated a shortcut?

Ardour 7.4 from here, running on Linux.

ETA: Here are a couple of screenshots:

The audio starts at the second marker, but after trimming the start of the region, the audio moves later and no longer starts at the second marker:

[Lost_Highway]

I’ve checked the other playlists on this track and this weird behaviour only occurs on one of them, all the others behave as expected.

The one with the odd behaviour is a copy of one of the other playlists, that’s the only thing I can think that marks it out as different.

[seablade]

So random question, is it the audio starts later and becomes out of sync, or is it just a visual issue and the audio itself plays back in the correct position?

  Seablade

[Lost_Highway]

The audio starts later and is out of sync as well as being visibly later.