Big-IQ stats last collection date stuck at unix epoch?

I also have this issue with the following conditions:

1xBIG-IQ (v7.1.0.3)

2xDCDs

1xBIG-IP cluster (15.1.2.1), where one BIG-IP shows correct stats date, but the other stucks at 01.01.1970

Both BIG-IPs have AVR provisioned.

Both BIG-IPs can be pinged and telneted (on port 443) from both DCDs

Running a tcpdump on both DCDs with filter on the failed BIG-IP shows NO packets, where in comparison to the working BIG-IP I see packets initiated from the DCD.

I've already removed the affected device from BIG-IQ and rediscovered it again, but no success.

Do you have any other idea, what could be the reason/issue here? Or anything else I can try for troubleshooting to further investigate this issue?

Thank you!

Regards Stefan :)