The Bug:
You cannot fly and sprint simultaneously in creative mode when only the lower half of your body is submerged in water.
Steps to Reproduce:
Switch into creative mode if not already.
Summon a large body of water below you that is only a singular block deep.
/fill ~-10 ~-1 ~-10 ~10 ~-1 ~10 minecraft:waterSubmerge the lower half of your body in the water and begin flying.
Without changing your y level, attempt to fly and sprint simultaneously.
Take note as to whether or not you can fly and sprint simultaneously in creative mode when only the lower half of your body is submerged in water.
Observed Behavior:
You cannot fly and sprint simultaneously.
Expected Behavior:
You would be able to fly and sprint simultaneously.
This is actually a duplicate of MC-133414.