I have been noticing bug damage on some of the basil leaves (young plants brought in last month). Soon saw it wasn't just the brought-in, but on some left outside. The infestation started when there were outside.
The top of the leaf looks like it has leaf miner damage (light colored patches). The underside has been ate-up! As I don't see the culprit, hard to spray or remove. If this were a different sort of plant, could try a light does of systemic (but not a good idea on plant that we eat the leaves!). I have tried the soap-water spray, let be, then wash up and down side of leaves with water. I am removing the worst infected leaves.
The only clue is sometimes I spot a small white insect, (not fuzzy or a worm).