Relates to MC-93768 and MC-312014.
Depending on how you collide with water, it is possible for bubble particles to be created completely outwith the space of the water block itself. Since this causes them to vanish in the very next frame, the overall visual outcome is quite strange, implying they should not have been created in such a state in the first place.
This is easiest to reproduce when entering water from the side: a restrained water source, or the side of a waterfall, can be used to reproduce this.
Simply walk into water from the side while looking straight down to reproduce.
Expected results: bubbles would only appear inside of the water
Actual results: many bubbles appear outside of the water, in the middle of the air, then instantly disappear
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