Minecraft 18w30b, 1.14.4, 1.15 Pre-Release 2, 1.16.2, 20w51a, 21w03a, 1.16.5, 21w06a, 21w08b, 21w11a, 1.17 Pre-release 2, 1.17, 1.17.1
First, this is related to
MC-72368 (fixed 3 years ago). This bugfix leads to an inconsistency with cactus/water interaction.
*How to reproduce:*
Place some cacti in a 1 deep pond of water, it works fine. Now flood the top to make a 2 deep pond and all cacti break.
*What I expected to happen:*
Water touching a cactus from any side consistently breaking or not breaking the cactus.
*What happens instead:*
Water touching a cactus from a side does not break it, from the top it does break it. It's not really intuitive or consistent.
Water does not break cacti from any angle.