I've had similar issues where after guiding all my allay through a nether portal (which is annoying cuz their path finding avoids portals), I had to go back to get one that had gone back again so I tied my other 7 to a fence post. When I got back they all escaped their leads. But even weirder was that 5 out of the 8 Allay I took with me can no longer be tied to a lead, but they can still change items.
And now that I reloaded my game one of them despawned
i'm going to be sad when this parity gets 'fixed'. My allay will soon lose her grumpy friend. Guess i need to make the most of their last moments together unless mojang makes an exception to the rule if nametags are used.