Muting/adding/removing parts on one track does the same to another?

I’m experiencing the strangest thing where if I add/move/edit parts on one track, the same things happen on another track.

I should mention that the tracks acting “linked” in this way are either duplicates of the first one, or a render-in-place of it. But, I’ve duplicated and rendered tracks many times without them behaving this way

Here’s a video of what I’m describing in case my description isn’t clear - note how I’m muting one part, and then parts on other tracks get muted too.

Did these tracks somehow get “linked” in some way? If so, why, and how do I unlink them?

Sorry to say that I can’t reproduce any behavior of your video, even after having done both a duplicate track of an instrument one, and a render in place of it. I even tried to link them in some ways (Mute/Solo/Listen, Selection…) in the MIxConsole, just in case… Nothing.

So, the usual suggestion, in this kind of cases : have you tried this after having relaunch Cubase in safe mode, using the Disable program preferences option ?

Edit: Saw the video, this is something else, and weird.

Weird indeed eh? Unless anyone knows what it is, I’ll assume it’s some bug or glitch. I’ve never had this happen on any other project (and only ones derived from a particular original track on this project) so I’ll probably just work around it, unless I happen to come across the same issue in the future.

I have had this happening to me on a project in Cubase 11… Only that one project. Frustrated the heck out of me… never to be seen again.
PS. I don’t remember how, or even if I fixed it before the mix/project were finished

You probably checked this already but could it be that Group Editing is activated in any of the folders that these tracks reside in?

If you create a new empty Project and import all the Tracks into it does the problem follow along?