MIDI input cutting out below Middle C

I’m doing a lot of Live MIDI input, which generally works amazingly well, but I’ve started running into an odd problem.

Occasionally, notes below middle C will not be recorded. I can hear the samples being played, so the keyboard is definitely generating the note, but Dorico is not entering it into the score.

These are all single-staff instruments (voices, strings), but it’s as if the Split point is being applied. Does Divisi use the split? I’m not seeing the notes in a lower staff. And it’s happening inconsistently.

I’ll try turning off Split Point.