You can waterlog cactus

What do you mean by "not other blocks?" Most non-full blocks can be waterlogged.

wait but you said most

I am trying to understand exactly what behavior you are reporting as a bug. Are you reporting that cactus can be waterlogged? (Just like you can waterlog stairs, slabs, leaves, repeaters, etc.)

yes

Ok. I'm not sure if that's a bug or and intended feature, so Mojang will have to decide on it. It could actually be useful and interesting for making traps and decoration underwater. You could think of a waterlogged cactus as being like a stinging anemone.

For comparison, sugarcane cannot be waterlogged, but leaves can. We might expect cactus to behave more like tree leaves because it's naturally a sturdy plant.

Affects 1.19.22

Affect 1.19.83