Reason:

The palm rejection don't work great on my tablet so I always accidentally erase contents when zooming or writing without noticing it. By the time I see the damage, I may not even remember what was there.

Proposed Fix:

Add an option to popup a notification on the top of the screen when an erase is triggered. Simply say erased and put a undo button next to it. This would notify users when they erase something, preventing accidental erase from happening unnoticed.