Of course it's possible. I said I'm not ruling out user errors. But then again, I had several tens of pictures with it. All look like that. And I stress, in the plant pic I heard the focus confirmation beep. Also, it was not a private lens. It was loaned to me by Canon Israel. Logic suggests they make sure the lenses they own are "good copies". I'll check this with them and report back.
I would not assume this! I used a 100-400 lens from Canon on a workshop last year and every photo was less then sharp. Never seen this in any other lens. I've shot with other 100-400 that were great.
JT