RF 100-500 clunking and no fstop read out on start up

[boney]

Hi first time poster here.
A week ago when I connected my 100- 500 to my r5 the first weird thing I noticed was that the readout on the back of the camera did not include the f-stop information.
When I tried to look through the viewfinder the screen was in blackout but the focus point (in this case the wide zone) was visible.
Turned the camera off and back on and the lens started clunking 2-4 times and then eventually it seemed like everything worked as normal.
The camera went into sleep mode and when I woke it up to shoot a bird the blackout and clunking started again.
Once the focus is working it is fine unless you change you focal distance alot then it locks up again and it takes a few bumps with the shutter button to get it working again.
Once I got home I gave all the connection points both on the camera and the lens a good clean even including a tooth brushing between the nodes just in case something was caught up in there. All of this was to no avail and I tried the lens on an R7 and the lens did the same stuff so it wasn't my R5 that is at fault.
I have run out of ideas so if anyone has some useful information it would be greatly appreciated.
Tony

 

[shadowsports]

Greetings,
Are you in the US? Make sure you haven't moved any of the mode switches on the lens in between on/off, or limiter etc. Since the behavior occurs on two body's, I think its time to contact Canon. Hopefully you have a CarePak.

The lens has to be registered at MyCanon

Then you will see your support options, and can arrange for inspection and service.

 

[boney]

Yes the lens is still under guarantee thank goodness.
I have checked the switches.Thanks for the reply