I also wonder if it has anything to do with your polymeter. If you can share it (or prefer to PM) I’d be happy to try opening it on my mac to see what happens.
I had been experimenting with all kinds of polymeter (on another – now closed – project), and I just deleted a quintuplet from this one, but it had no effect.
Regarding this: actually, I almost always hide signposts, so this problem may have existed for some time without my having noticed. At any rate, when I ask Dorico to show signposts on these older projects, no signposts appear at all.
(I’m trying to find an emoticon for “embarrassed”!)
When you were kindly helping me out, earlier today, I noticed that a signpost for (what I assumed to be) a tuplet showed up in green in your gif:
. . . and I noticed that no such signposts were showing up in my own version of the same thing.
Now that you mention it, I now recall that, yes, they only show up when things won’t otherwise be visible! (imagine two “embarrassed” emoticons!) , and – sure enough – the above file does display signposts (tempo, time signature, etc) when I use properties to hide them:
Thanks, Leo and Romanos401 . . . I’m sorry to have troubled you over this one!!