Hello. I just came across a minor issue.
If you mask a mesh instance while the original mesh is hidden, you cannot clear the mask (either by the drag gesture or by the clear mask button) until the original is unhidden.
You CAN use other tools on the instance while the original is hidden, and this doesn’t seem to affect the inverse (clear mask on original while instance is hidden).
I’m having a blast with this app, by the way. Picked up an iPad just for this after trying a friends. Absolutely loving sculpting outside in nature.