An Update on My Canon 24-105mm F4L Problem

I wrote a while ago about the issues I was having with my Canon RF24-105mm F4L. I noted that for some bizarre reason, the lens got softer at 24mm as you stopped down from f4. This is the opposite of what normally happens with a lens. I went through significant testing to make sure I wasn’t doing something stupid and to try to identify the problem. I also contacted Canon, and they said this was not…