Was I seeing things or . . . . ?

[Conifer Dada]

I was in-world at my place in Yosu, on Jeogeot mainland today. Everything was working fine. I noticed the mainland terrain had changed from that greeny-grey stony grass that it's always been to a much lusher green grass that's found elsewhere on Jeogeot. The same change had happened to all the adjacent sims. The new terrain texture was about the same colour as my lawn, which is on a flat prim.

Anyway, I logged out and logged back in and the terrain texture was back to the old greeny grey "boiled cabbage" texture. I can live with that but the other texture was nicer! 

What I'm wondering is what sort of error caused the wrong terrain texture to appear when I didn't visit any other sims during that log-in?

[Starberry Passion]

You probably seen PBR textures on your land, before you relogged. Lindens were probably playing with PBR land textures and seeing how it would work. I assume they're slowly updating mainland, slowly or just partially.

[Conifer Dada]

I looked at the region details and the lush green terrain texture I saw was that set for higher land in the region. It seems like the levels must have got mixed up by the viewer.