The bug
If a player presses "sprint" key when moving in creative mode underwater, it instantly switches to "swimming mode." The player can still toggle flying by double-tapping space, but the swimming controls will override that state. Thus, it is possible to be both swimming and flying at the same time.
Expected behavior would be:
Creative players never swim while in "flying state"
Creative players can swim like survival while not flying
How to reproduce
Move in water when being in creative mode
Press "ctrl" or "sprint" key
"Swimming mode" is toggled on
If the player swims / sinks towards the bottom sometimes gets stuck and cannot move up / stop flying / swim up
The issue can be fixed by looking up (this toggles the "swimming mode" off) or switching into other gamemode.
Note: Spectator mode is not affected (anymore).
Related issues
is duplicated by
relates to
Attachments
Comments


Confirmed, maybe related to MC-125188
Updated the description slightly to note this also affects spectator mode

Confirmed for 18w07c

comfirmed for 18w08b
And you will stop flying after swimming in creative mode.

Im not 100% sure this is related but... If you go into water 1 block deep and start swimming an start to "Sprint" swim you will sink halfway into the block below and thus now be classified as underwater

No, that's a different issue. Please create a report (if it doesn't exist already) and also put screenshots with F3+B active in it.

same issue exists in 18w11a

This issue still exist in 18w15a

It doesn't seem to affect spectator mode in 18w15a though, so it's partially fixed.