Identifying yellow spots on Phalaenopsis leaf

[MateoinLosAngeles]

Hi all,

I moved this old (third blooming) Phal to a brighter spot and noticed a few yellow spots on the leaf.

Attaching photos.

The spots don't have a smell and, albeit translucent, they aren't mushy. I noticed when I took the photo with the flash on a brown cast would show underneath but not on top of the leaf. On top of the leaf I did notice a slight blister-like bump on the yellow spot, but the blister felt rigid and hard, not filled with water or any liquid. This blister-like texture was hard to photograph.

Any idea of what this might be?