Whenever a mob begins to drown, the damage immunity gained is the same value for standard damage types (which is .5 seconds), making it so that mobs drown at twice the speed that players do (which is 1 second).
Steps to Reproduce
Build an encased 3x3 box
Fill it with water
Spawn any mob in that box (suggesting a fox here because of higher health yet smaller size: MCPE-48233)
If done correctly, when this mob begins to drown, they will take damage every half of a second, the same immunity timer given for projectile and melee damage.
Video Examples
Linked issues
is duplicated by 2
Attachments
Comments 3
While this issue is fairly non-impactful to most mobs, this difference in timing is particularly lethal to allays as it completely outpaces their natural regeneration.
In my case, I lost 2 allays to drowning damage minutes after I rescued them due to the presence of a waterfall in my base.
Affects 1.16.100
Affects 1.16.200.56 Beta