Weird display glitch and irresponsiveness in piano roll

Hello, very strange issue that I never had before.

Running Cubase 9.0.30 build 266 64bit on Mac OS 10.13.2.

Piano roll seems to go crazy after a few minutes. If I change the length of a note, if I edit a controller, the changes aren’t visible. For example if I change a velocity from 127 to 20, and make that long note very short, the editor still displays a loud long note instead of a short quiet one.

The display only seems to catch up to what happened when:

  • I wait several seconds (!!) or…
  • the song is playing and the play cursor goes over the changes (it “reveals” them as it’s passing over the changed notes and controller).

The problem happens in the piano roll editor (both full the window editor and the one in project view).
The problem DOESN’T happen with “Edit In-Place”.

Restarting Cubase fixes the problem only for a few minutes before it starts doing it again.

Maybe unrelated but I updated Mac OS to the latest security updated from Jan 8, and noticed that problem.

– UPDATE –

So far it seems to be happening only with one project. I’m investigating what could be causing it. Weirdest issue yet…