Messy time signatures in galley view

I get this often when I change time signatures, and it’s annoying. The mess only appears in Galley view, though, so it won’t print. But why does this happen?

I’ve never seen this …

That’s the reply I got from the Facebook forum, too. But as I said, I see this often, and I wonder how to get rid of it.

If you reset everything to factory defaults (using library manager), does the problem disappear? If it does, then one of your settings has caused it.

Following … and really curious, which setting could possibly cause this …

I’d need to see the project and have the steps to reproduce the problem to say with certainty what’s going on, but my guess is that this is an artifact of the way Dorico chunks up the music for spacing and layout in galley view.

It effectively splits the music into mini-systems, and lays them out one after another. I suspect that the places where the time signatures are over-printing the music are at the “joins” between these chunks of music, though of course normally this works without issue, so there is presumably something else going on in this case.