Midi Punch In part not playing back

I’ve recorded a midi punch in on a bass part in Cubase 10.5 on a Mac running Mojave. The notes appear. They have velocity. But the new section WILL NOT PLAY. The bass part plays before and after, but not during the new part. What am I missing here? It’s driving me nuts.

If I copy the part to another active midi part, the same thing happens: sounds before the new part, no sound during it, sound after.

If I copy the notes and paste them into a drawn box part, THEN the notes play. WTF?

Can anyone explain this behavior to me, and what I’m missing? I thought I should be able to just punch in and punch out and have the part playback as is…I’m wondering now if this is related to upgrading to 10.5. Probably should have waited…


Isn’t the MIDI Part muted?