EOS R5 Mark II with lens RF100-400mm F5.6-8 IS USM - Every now and then fails to achieve AF

[lwatawala]

Camera: R5 Mark II ( Camera Firmware Ver 1.0.2)
Lens:      RF 100 - 400mm F5.6 - 8 IS USM (Lens Firmware Ver 1.0.3)

Every now and then, this Camera/Lens combination fails to achieve AF.

I'm using AF-ON back button with the following settings:
      AF start position : Manual selection
      AF operation : SERVO
      AF Area : Around
      Whole area tracking servo AF : ON
      Subject to detect : Animal
      Eye detection : AUTO
      Servo AF characteristics : M

I can't say for sure, but it may be getting in to this situation after the camera goes through an auto power off (not consistently)

One way I have been able correct this situation is by turning the camera  OFF and ON.

Anyone has experienced this? Any suggestions on how I can prevent this from happening.

Thanks.

[Waddizzle]

Thanks again, for your replies.  

When you press the [AF-ON] button, do you keep it pressed until you complete the shot?

[lwatawala]

I have used the camera with "Lens Drive when AF is Impossible" Enabled for some time now and haven't seen the issue I encountered with focusing. So, I have accepted this as the solution.

Thank you everyone for your input and suggestions.