Ficus petiolaris Leaf Spots, Excretions?

[hemmy]

I’m looking for help diagnosing a weird leaf damage issue on a Ficus. This is my only Ficus petiolaris and it gets these weird excretions and cell death on the leafs that I’ve never seen on any of the other ~7 Ficus species that I grow. Relative to ficus the leaves seem to be pretty short-lived, ~3-4 months. They come out in pristine condition but after a while they start developing these white spots on the underside and cell death on top side. The top damage is dead tissue that is small in area but spread around. It doesn’t appear to have any fungal spores under 10x magnification. It also doesn’t look like my experience with sunburn.

 

[hemmy]

Looking close at the excretions, I do not believe they are scale. They are clear, irregular in shape, and under 10x magnification I cannot see any insect.

They scrape off to reveal a burst cell or set of cells beneath. They have no flavor (not a salt).

 

[hemmy]

There is some black mold, very rarely at only a few locations. I think it is opportunistic and not the cause.

This closeup of top necrotic areas.