You dismount horses when you go into water more than two blocks deep and you cant get them out even with the nameless lead.

I had thought that the horse would swim and swim faster than a person but slower than a boat. I had also thought that the lead would make it swim to shore but it didn't
because it started acting like a sheep does when it eats grass and eventually drowned. This happened to three horses.

I jumped into the water and I was dismounted involuntarily and no matter what I did the horse wouldn't come out of the water not even when the nameless lead was on him.

Steps to Reproduce:
1.Ride a horse into water more than two blocks deep.
2.attempt to put a lead on him.