Leaf eaters would be noticable, and you wouldn't need a magnifying glass. Mites start looking like dead spots everywhere because they only consume a very small radius. looks like polka dots a millimeter or less in diameter.
I had very similar issues, and i still see it on some growth, but it's mostly gone. It came from over nuting nitrogen, You would be able to tell if you are having the same issue by checking the leaf color around it. if the rest of the leaves are a lush green and some come out deformed and patchy it's a sign you might be giving it too much nitrogen. It could also have been damage to the leaves as they emerged, much smaller, when they grow out and flatten small damage becomes larger damage as they stretch. Mostly check to see if it's happening to new growth.
Nitrogen OD'ing also creates mutations where some leaves will twist and contort. Look to see if you have signs of mutated leaves.
Please help!!
