That's a beautiful catt.. I love the dark colors. Is it fragrant?
It looks like a bifoliate and they are very sensitive to changes in their environment. I've had them refuse to bloom for one whole blooming season after being repotted. Recently I found out that bifloliate catts should only be repotted when new roots have just started to grow.
The leaves look to me like there's more going on than just sun burn. Maybe the spots started out as sunburn but a fungus or bacteria infected the burned areas. Mites is another possibility. If you have Physan 20 you might want to use it. If not, just wash both sides of the leaves with soap and water, some people add some rubbing alcohol, and place the orchid in a little less light. Hopefully it will start growing some healthy new foliage. Good luck.