Hey Hypocrita,
So your issue looks like it could be related to the bounds of your landscape. If you are using World Position Offset or Displacement within your material and are pushing the vertices of your object past its bounds, then certain areas or the entire landscape will begin to flicker.
To counter-act this behavior we’ve added the Positive and Negative bounds extension for the landscape actor. See the below image for directions on how to modify these settings.
Let me know if you have further questions or need additional assistance.
Cheers,