What made these "tracks"?

[Stray59]

Hey everyone;
Just purchased two B. dygbyana x L. purpurata crosses that I found in the "bagged orchids" at Lowe's. One looked really healthy and I really did not inspect the second one as I got distracted. When I got home, I placed both under my florescent lights and then I noticed dark spots on the one I had not looked at quite so well. Upon inspection, I found the underside of the leaf had indentations with what looks like little "tracks" leading from them. The top of the leaf does not look bad but near the base of the leaf there is yellowing in blotches. On the one plant, four leaves have these markings.
I took pics and would appreciate any input as to what I brought home.

Underside with light showing through; Dark spots

Underside with top lighting; indentations and "trails"

Top of leaf with top lighting; indentations

Top of leaf, near base, top lighting - yellow blotch
Isn't it always the one you don't look at well? Any help is appreciated!
Steve