I have a new R8 and when I first installed a new RF-50, the AF wasn't working in any Manual camera modes. Only MF is displayed when I tried switching focus modes. But the AF was working fine when I switched to Auto mode or in to Video mode. I rechecked AF with my other lenses and they all worked fine in all modes. I did a camera reset and AF started working in any Manual modes. But when I made any changes to the camera settings like dial functions, AF stops working on the RF-50 again in any Manual modes. There doesn't seem to be firmware updates for either the lens or the R8 at this time.
For lenses WITHOUT an AF/MF on them. The focus mode must be changed via the camera menu. Not lens itself.
Reset the camera and custom functions back to factory default.
Do those lenses have an AF/MF switch on them.
09/26/2023: New firmware updates are available.
08/18/2023: Canon EOS R5 C training series is released.
07/31/2023: New firmware updates are available.
05/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
03/30/2023: New firmware updates are available.