Corrock plants are immediately waterlogged upon conversion. Works for all corrock plants in all dimensions, as a side effect, allowing water in the nether.
Example

Applies to 1.16.5 (not tested on other versions)

Corrock is an unfinished feature in 1.16.5, so any bugs with it on public 1.16.5 versions are very minor.
I will see if the issue still happens on 1.19.

This issue is not happening in 1.19. But I noticed that waterlogged variants do not convert to their dimension variant.
It is staying as nether variant for like 3 minutes. Non-waterlogged variants converts fine.

That feature is intentional. Corrock that gets touched by water becomes Petrified Corrock.

Oh. That means that there is no issue in 1.19 at all then.

Just going to close this issue because Corrock is incomplete on 1.16.5, and this issue is not prevalent on 1.19.