Update again. They "fixed" the auto focus issue, but it really didn't fix it completely. Now, I can focus lens up to about 300mm, at 400 mm and above, it just will NOT focus if "Lens drive when AF impossible" is set to off. When set to ON, it focuses perfectly. However, tech support told me that with it ON, focus is not as fast. I tested my RF 100-500 on a friend's R5 and it focuses perfectly with "Lens drive when AF impossible" either on or off.
At the suggestion of tech support at Canon, I sent it back in to be repaired. I have never been so disappointed with Canon service. They did give me a next day label and they received it on 6/17. I emailed them on 6/28 asking for the status. They did not return an email until July 1, and then said that a tech tried to reach me on 6/18, but have no emails and not phone messages, so I am not sure that anyone actually tried to reach me, and if they did, didn't why would they not try multiple times if they couldn't reach me. It is now close to three weeks that they have had my camera. I gave a detail reply to their email on July 1 and still have not heard back from them.
I wish that I had been able to return the camera to B&H, but due to backorder on the RF 100-500, it was past the return date when I first identified the problem. It has been at Canon now a total of five weeks for the two "repairs" and I still don't have a camera.
I strongly suggest that you return it if it isn't working right and try to buy another one, because I know that some of them do work properly and Canon support is close to worthless these days.
Actually, another friend of mine just got a Sony a1 and he is thrilled with it. I think I made a big mistake staying with Canon and now wish I had switched to Sony. (I really can't believe that I just said that).