A few times after the last few updates, using paint and sculpt tools would cause all landscape tiles to start flickering, like z fighting with void.
Hovering the brush tool over an affected landscape tile the reticle is offset to the mouse curser.
Clicking on it once with the hydro sculpt tool, fixes it, there is also a noticable change visually to the landscape tile and the reticle correctly lines up with the mouse.
After the last update the flickering stopped, but the landscape still goes out of alignment, until I manually click on all 64 landscape tiles with the hydro tool.
It seems to stay aligned until UEFN gets an update. Which probably just indicates the landscape is getting worked on and everything needs refreshing, but its not automatically doing it.
Build Landscape, doesn’t fix it, but Build Landscape doesn’t seem as magical and wonderful as it used to, I miss the message log pop up
I would suggest closing the launched session, click on each tile with a hydro sculpt tool, then build hlods if needed and then launch a session to test