VB3m sounds intermittently in GarageBand on iOS

If you hear a note every once in a while when you tap on GarageBand's touch keyboard, you're actually hearing 2 or 3 notes every 16, and the reason is because VB3m is a multi-channel instrument, responds on 3 separate channels for upper, lower and pedalboard, and GarageBand cycles Midi channel at every note, so once you play the upper, next you play the lower, next you might catch a note in the pedalboard range, then silent for 13 notes, then back at the upper channel again.

It's not VB3m's fault, it's how GarageBand works and we can't explain
why they chose to make the keyboard work that way and did not include
an option to pick a fixed channel.

We suggest using a different AUv3 host. Try AUM, Camelot, Cubasis...