Cannon R5 Autofocus Issues

I have been shooting Canon DSLRs for many years and recently purchased an R5 to complement a 5D MkIII and a 7D MkII. The reviews on the autofocus for wildlife and particularly bird photography were so positive I couldn't resist. I normally use the  expanded center focus point (either 4 or 6 peripheral points) in one shot or servo mode. My previous experience with Canon autofocus is that it locks onto the closest object that any part of the center point touches. My R5 however seems to want to lock onto the background unless I am very careful to position the center point exactly where I want to focus. I have disabled the touch screen to prevent accidentally repositioning the focus point by inadvertently touching the screen. Sometimes the autofocus selects the background anyway and I've missed too many good shots. My 7D does not behave this way at all when set up exactly the same way. I have primarily been using  Canon 100-400 L IS 2 with an EF to RF adapter and upgraded to the most recent firmware v 1.6. I realize that this may be nothing more than operator error due to a new piece of equipment but wonder if anyone else has had a similar problem of if the camera needs to be evaluated by Canon. Any words of wisdom would be appreciated