I obtained an allay in my world shortly after they were introduced into the main game. I duplicated this allay 3 times.

Since 1.19.51  I have been unable to duplicate any of these allays. Nothing happens when you click on the allay when it is dancing. 

I loaded a copy of the same world in creative. The old allays still do not duplicate. But any new allay created from a spawn egg does duplicate as expected.