Attaching screen recording.
This is happening to us here too, no amount of restarting the game or iPad seems to make it come back. Any time I try to import a custom skin, it's just totally blank/invisible.
Still happens here; iPad mini 4, iOS 13.3, Minecraft 1.14.1.
Thanks - surprising that search didn't turn that up for me when I looked....
Happens very regularly here on a current-model iPad mini. Sometimes sound just disappears for no reason I can discern.