When I began suffocating in sand, I took damage before the oxegen bubbles actually ran out. This also happened in water, but seems to be fixed (at least with the water).
Linked issues
Comments 2
The oxygen bubbles are not supposed to show when you suffocate in a solid block. See MCPE-34310
The oxygen bubbles are not supposed to show when you suffocate in a solid block. See MCPE-34310