This is the 4th leaf damaged. The plant is in a container. I have plenty of slugs and snails, but don't think this is damage done by slugs or snails. I don't see any snail trails and slugs normally don't get on my concrete side of the yard.

I tried to inspect the tree, checked every leaf underneath too. Did not find any insects. I did find some black spots on one of the leaf that I believe were eggs of some insects. I removed that leaf few days back just in case, but still something is bothering the plant.

Can you please help me identifying and/or controlling whatever it is.