I'm having issues with painting landscapes.

I’m new to UE4 and 3D dev in general. I’m not sure if this is an easy fix, an oversight on my part, or something truly wrong. I have 9 textures loaded onto a material, and initially, things were working fine, no issues whatsoever, I took a short break, returned to it to find that the ‘blank’ squares appear in random places throughout the level. They will be compiled on part of a landscape, but not on other parts of the same landscape. Some will just never compile and return to normal. They stay as these gray squares, which can still be painted on, however will not change. You can see the textures next to the edges blend into whatever texture you are painting on the gray areas with, but the gray area will never actually change. In the picture you can see 2 of these such squares with a space in between them. The space in between can be painted on freely with no trouble by all 9 textures. Is there any way to fix this? I’ve been working around where I know the squares are, but as seen here, some are particularly intrusive. This also happens on other landscapes in the same level. I’ve researched for hours on the subject and have not found a working solution. Thank you

Does this go away when you hit Save? I have the exact same bug in 4.25. Little patches/tiles that don’t compile correctly, then hit save and it goes away instantly. I tested 4.24 and the bug isn’t present there.