have you tried washing off the black spots? Just asking...

I understand coffee likes hazy afternoons, so full sun all day is too much for them. That might be causing the brown patches you didn't ask about.

Obviously, some kind of chewing critter is eating that leaf. Have you checked the soil? I'm kind of thinking slug, snail, or caterpillar. Maybe a teensy caterpillar would leave tiny black droppings.

I would probably soak the entire plant, pot and all, for about 5 minutes or more in water with a little NON ultra dish detergent. (The Ultra would strip the waxy coating off the leaves). That will kill bugs on the leaf surface and in the soil. No need to rinse. I do this with every plant and cutting I bring home; the plants never seem to mind. Sometimes I have to use a garbage can for the soaking.

The other possibility is a flying critter eating the leaves. The soap might deter it, horticultural oil might be better, but I'm not good with that stage...

I've moved it into some shade, so, the sunburn should get better. I cleaned off the plant and the pot, but didn't see anything other than what might have been a couple thrips? They are squished now. I was thinking of visiting a local nursery to pick up some ladybugs. I have some other pots that need cleaning out anyways...

Wait, so, like, dunk the whole thing? The soap isn't bad for the roots?

Nope, not bad for roots. I've heard it actually acts like a mild fertilizer. Just make sure you don't use the Ultra. I killed a dozen vireya trusses by grabbing the wrong bottle of detergent.