holes in landscape nearby lake ingame

There is holes in landscape nearby lake ingame but not in editor. How to fix it ?

Wow, haven’t seen that before…

Its even generating rock on the broken seam.

Have you deleted and remade either the terrain or lake ?
have you only got one waterbrush for that terrain ?
all I can imagine at the moment other than a nasty glitch is an old waterbrush left over from an old lake that was set to affect landscape…but then that should be able to be seen from editor anyway…

It does look like an outdated HLOD though, but does landscape even do HLODs now ???