Some zones not showing detail until zooming all the way

[pqee]

When zoomed out all the Pandaria zones show their undetailed textures that just shows their zone name on them. When mousing over a zone it usually changes to the detailed textures.

My problem is randomly some zones stop showing their detailed textures on mouseover unless I zoom the map in extremely far where I'm only viewing a tiny portion of the zone, defeating the purpose of seeing the whole zone properly. I've had it where half the Pandaria zones work fine on mouse-over, the other half do nothing.

I don't know how to provide more info as it seems random when it starts doing it. Hoping someone else gets this and knows what might cause it.