Huge landscape seams

All of a sudden we have huge seams in our landscape. It seems to only occur around a certain area but nothing I do with the Landscape sculpting tools seems to affect it.

Here are a few screenshots:

Didn’t realize how dark this picture got. It shows the character sinking through the bugged part of the landscape.

How can I fix this? Our landscape is huge so I’m not entirely sure how long it’s been like this.


Can you bump these? Would love to get help with this, I can’t figure it out.