Without a picture it's anyone's guess, but mine would be leaf-cutter bees (good guys), of rosefly slugs aka sawfly larvae which eat from the bottom of the leaf and leaf a sort of window pane affect. They can be washed off with a strong spray off water or, if Covids left you with lots of time on your hands and you don't have many roses, you can squish or remove them individually. They move like wildfire so as soon as you see any damage spring into action. When they're done feeding they drop to the ground to pupate.
