Discoloration on phal leaves... virus/sun damage?

[kmits]

I got this phal about a month ago from a greenhouse. I initially assumed the yellow spots were from water sitting on the leaves while it was in the sun. I'm not concerned with the purple parts as I've heard some phals can show this pigmentation if they produce rich purple/red flowers (and it's not just the leaves that are purple, root tips and spike are also the same color.) Since I thought it was sun damage I was expecting the spots to turn brown and get dry, but they haven't and I've recently found some yellow spots on the underside of one of the leaves but they do not show on the top. This phal hasn't been in direct light since I got it and none of the orchids that share a shelf with this one have any sun damage. Is this a virus, mold or possibly just old sun damage? Any thoughts or help would be greatly appreciated.