I have also encountered this issue multiple times. It occoured most frequently when breeding horses with 15 hearts each. I play pure vanilla survival.
The issue still persists.
I have also encountered this same issue multiple times on PC. Especially when leading a horse through the water with a lead, and then trying to ride it after arriving on the shore.
It is an old world (even older than the caves update), so that might be the cause. However, the addition of the second Ender dragon is still rather new.