Cattleya walkeriana developing dark spots and yellowing on leaves

[NYCorchidman]

That is not sunburn.

I would think virus or fungal disease.
It does not look like the dreaded black rot ( pythium), which usually shows no advancing yellow margin, plus no black round circles like on your leaves. Black rot just eats up the plant basically, and quite fast.
Send a leaf for a testing.
I had this same thing happening on a Cattleya hybrid. It happened within one week of purchase. It turned out to be virused. I tossed it without a second thought. It was sad because the plant otherwise seems good. It had white flowers with no distortion. so I could never have guessed.