When exploring an underwater cave, I attempted to clear out all of the water in the environment, but when I passed by a glow lichen it wouldn't replace the water and would repeatedly spawn water in and out.

To replicate, I simply put into a repeating command block set to run repeatedly:

execute as @p at @s run fill ~-10 ~-10 ~-10 ~10 ~10 ~10 air replace water

The images do not capture the entire phasing in and out, but note that it very quickly was glitching the water in and out cyclically.

Upon further testing, I noticed that this seems to apply to any waterlogged blocks. To replicate, just grab a water bucket and run that command when near it to see its effects.