The wings on the insect seem to be in focus & that's what cupic has focused on. The lens is not vertical to the plane that we are all looking at; that is the brick that the insect has alighted on. Therefore the centre of the depth of field won't be vertical either; it will be at the same angle as the lens.
I reckon the lens is OK.
Coises; I can't get my scanner to work to post a sketch of what I mean. I'll keep trying