I tried your steps now and after a lot of reactivating the project back and forth, all except the first connection dissapeared. Interesting was, that after a few more back and forth of activating the two projects, they also re-appeared. And after even more they also dissapeared again. So it seems to be some kind of gamble if they get resored properly.
All of that happend in my case only in the second (‘save as new version’) version so far.
But in my original thread (that you quoted) I mentioned the problem in a project that was still the original version of the project and not a duplicated or something like that (and there it was also with other plugins, not only with steinberg and not only with volume)
Also the duplicating of tracks didn’t copy the modulators exept for the first one. When the project was in the state where on the original track the connections were gone, on the duplicated tracks all connections were gone.
So it seems as this bug is reducing the count of connections by 2. On the track with orig. 3 connections only 1 remains, and on the tracks with 1 none remain.
Win11, Cubase 15.0.30