The following applies to instument midi files as well as drum midi files. I got the impression from the forum that this bug had been squashed in an earlier update ( I have only recently bought C3 ) but presumably it hasn’t. I know there is a work around for this but it really shouldn’t be necessary.
Drum midi file inserted into a track changes the track’s assigned AUv3.
Insert a drum AUv3 into a midi track - I have tried Digistix and EG Pulse.
Double click or drag a Factory or User drum midi file from the Media bay into the selected track.
The drum midi file is inserted without changing the assigned AUv3.
The assigned AUv3 is replaced by a Factory drum instrument.
Ipad Pro (10.5") 2017