Phallenopsis: Mesophyll Cell Collapse? Thrips?

[Karlaam_]

Hi everyone!
So the story is that I went on vacation for 8 days, and when I came back, I found one of my orchid's leaves with symptoms of what I thought was mesophyll cell collapse. Because the damage was all over the leaf, I decided to remove it without a more careful inspection (bad idea).
A few weeks have gone by, and now it's happening again, even though I've been more careful with my plant's care.
At the back of the leaf, I noticed a big brownish spot with small white spots around. Also, there are two cocoon-like lumps and a hole(?). See pictures attached.
These signs are making me think that this might be caused by bugs, but I am not sure about it.
Also, I removed some of the substrate to make a closer inspection of the roots, and though they seem old, I didn't find signs of rot.

Does anyone knows what might this be? Any help would be highly appreciated.

Thank you!