Thank you, thank you, a year and a half of waiting for this moment.
ProfMobius is better than Dinnerbone. 😛
I had this problem on multiple servers, but not only to "repair". it is hard to explain. I leave a video of the problem.
summary of the problem.
https://www.youtube.com/watch?v=4ti5_v2DKaI
example (m 8:30):
https://youtu.be/ogM9BdiSlVo?t=510
Rarely happens in single player as well, but is very rare.
Please open this bug
This should be only for player-horse, as it hinders the development of custom maps.
Suggestion title: "All Mobs are extremely slow in the water".
Español: "Todos los Mobs son extremadamente lentos en el agua":
please do not discuss a joke. What is important is repaired bug =)