Can't edit WaterbodyOcean anymore; landscape transports down

Hey I’m working on a set which uses the new WaterBodyOcean system.
I haven’t worked on it in a few weeks and just came back to it.

However when I edit the landscape or the WaterBodyOcean the landscape just jumps down. I can’t undo it either.

A screenrecording of the problem:

Does anyone know what’s going on here?

Fixed the link!

No you didnt