I also tried with the firefox snap on 21.10 with Wayland and couldn't reproduce a crash refreshing snapd from stable -> edge and back again.
I can however easily reproduce the same crash after changing the cursor theme to DMZ White on my 21.10 Wayland session, so that bug is for sure happening. @osomon, which cursor theme did you have configured when you saw the firefox crash?
I also tried with the firefox snap on 21.10 with Wayland and couldn't reproduce a crash refreshing snapd from stable -> edge and back again.
I can however easily reproduce the same crash after changing the cursor theme to DMZ White on my 21.10 Wayland session, so that bug is for sure happening. @osomon, which cursor theme did you have configured when you saw the firefox crash?