I can't see where to post this question, so I'll start here...
I'm making myself a new neighbourhood map, imported it from SC4, created the neighbourhood based on that template (lush/temperate) and took a screenshot. Then I typed in the cheat to change the terrain type for another screenshot, but when I changed it, the colours were very blocky and weird (see photos). When I change it back to temperate, it's also weird and stuck that way.
What's wrong? Thanks.

Does it persist if you reload the neighbourhood? Try opening another neighbourhood then going back to that one.

Yes it does. Also if I make a hood with a terrain that isn't lush it has the grid visible, as part of the texture.

Like this:

Do you have any terrain modification overrides- custom roads, high res textures, that sort of thing?

No I made these with my DL folder removed, so no mods or anything at all.

Oh that's not quite true. I have some mini-lots installed including the sunnyside ones and the beach ones. Not sure how to remove them.

Ok I just tried completely quitting the game after changing the terrain, and it looks normal with the new terrain. But what causes that?

Oh, maybe a cache issue? So if you change the terrain, exit the game and reload, it looks okay?

It does but I don't want to have to do that every time I need to take a screenshot!