was it behind the crab the whole time?

No, there's nothing behind the crab. If I call the crab to come near me (before it fall on the left), the strange water disappear.

I suggest posting this bug in the main area of the Toki Tori 2 discussions rather than the Workshop area.
https://steamhost.cn/steamcommunity_com/app/201420/discussions/0/

I'm not sure if this bug occurs only in a workshop map or not. Anyway I can post in the main area too :)

Originally posted by watahaya:

I'm not sure if this bug occurs only in a workshop map or not. Anyway I can post in the main area too :)

Ah, sorry. I didn't notice your first sentence saying it occurred in your workshop map. Even so, I think the bug will have a greater chance of getting noticed in the main area as that's where the devs seem to frequent (though they do read here, too).

I hope so :)

There are some edge cases where the fluid system does not behave correctly, which are avoided in the main game. Of course these can be encountered when creating custom maps.

What you can do is create a small level that demonstrates the bug and send it with a description of the bug to support@twotribes.com.

For now the best you can do is tweak your level a bit to work around this bug. Be careful with hermits under fluids for example.

I'll try some. Anyway, the bug doesn't change the logic to solve the level.