Unknown Landscape paint glitch

Hi guys so I’ve come across this issue a few times now and have no clue why or how to fix it.

It seems to happen randomly with different paint textures. No real known cause that I can tell, it isn’t shaders rendering as it never goes away.

You’ve run out of texture space. Click all the textures in your material and change sampler source from ‘from texture asset’ to ‘shared: wrap’.