HI
just want to extend a question a little, seems like the topic is rather close
I have Reference atlas, HD and SD atlases (they are similar, SD atlas were made by duplicating HD atlas and making texture 2x smaller)
So, both atlases contain font named "Calibri". Sprites for the fonts display correctly in atlas inspector.
Next, I have calibri uifont that uses Reference atlas, and as far as I understand it takes "Calibri" sprite from one of the atlases, that reference atlas references to

The problem is, that when I switch atlases in my reference atlas, the font in the label is displayed correctly only for HD atlas, for SD atlas it loses it's coordinates (it seems like rect's position is OK, just the size of sprite isn't twice smaller for SD atlas).
Sprites' coords are set to "UV" for both HD and SD atlases.