Bug:
When you are partially in water while creative flying you cannot sprint fly. This also causes issues with the fov when you enter and leave water; as you are forced to fly normally lowering the fov and if you are still holding the sprint key it will shake.
Unsuprisingly this issue seems to have started with 1.13 no such issue happens in 1.12.

Steps to Reproduce:
1. find a body of water and fly above it
2. touch the water with your hitbox but keep your head still out the water
3. try to sprint fly
(alternatively you can sprintfly down into the water and see how it slows you once you touch it anywhere on your hitbox)

Observed Results:
When your hitbox is partialy in water you cannot sprint creative fly this also causes a fov shake when leaving (and entering but this is hard to perform on default controls) water while sprint creative flying.

Expected Results:
Smooth transition between water and air without slowdowns and creative sprint fly when partially in water like 1.12.