Leads are breaking randomly when they're tied to a fence when I exit and reload the world.

Unfortunately I haven't been able to find a way to replicate this exactly, as it doesn't seem to be every time, but so far it only seems to happen randomly with Allay and Frogs. Every once in a while when I load up the world I'll find that those mobs are no longer tied up and the leads are several blocks away from the fence I had them tied to. Its not much of a problem with the allay since they'll follow you if they're holding an item, and i always make sure they are, but frogs wander off. Leads have always been buggy on MCPE, but they've never done this before that I know of. Please look into this, its happened several times now and it's actually really annoying to chase the mobs down to tie them back up (Allay are not the easiest to leash on a touch interface...).