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).
Related issues
Comments


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