I don't have visual proof but bare with me, in water, if your swimming about sometimes when your against a block, your character will endlessly jump. To get out of it you just move into the water. Test it. It also seems to work if its a running water block...
Environment
Well, I run a windows 10 (like most other users) and there's nothing wrong with it. Considering it can run 41 mods and not lag.
Duplicate of MC-127224