[26.6.25 linux deb] When copy-pasting clips and then undo with ctrl-z creates empty video tracks and separates audio

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OS and Version (please complete the following information):

• Operating System: Linux Mint 22.3
• Shotcut Version: 26.6.25

I edit with 2 video tracks and 1 audio track (no other tracks created). I'm creating a teaching video. instructor video track is at the top (green screen) and bottom video track is a power point. To time the slides correctly with the speaking of the instructor, I cut the ppt track and move the two halves away from eachother, then I cut a piece of one of the halves and paste that multiple times in between to increase the frames that a slide is shown (extend the time that a slide is displayed) to match the spoken words of the instructor.

When I click ctrl-z (undo action), the undo action will be performed, but a new video track is added with an empty video in it. The instructor video's audio will be separated from the video track and added as a video at the end of the new video track as an additional video. To better understand, have a look at the screenshot. In the screenshot V1 track is the powerpoint track, V2 is the instructor track. I pressed ctrl-z 3 times, so 3 new video tracks are added.

Steps To Reproduce Follow the description

Expected behavior Undo action is performed without corrupting the top video track and not adding any new video tracks with empty video?

Screenshots

in the screenshot you can see that I clicked ctrl-z 3 times, so 3 new video tracks have been created and 3 times has the audio been separated from the original top video track. The has been placed at the end of the new track(s). Very ackward behavior.