[Observium] Huawei Sub-interfaces - no traffic captured

Hi all - I've recently migrated a number of services to new Huawei kit and successfully discovered the device and all sub-interfaces etc.

My problem is that Observium is not showing any traffic against any of the sub-interfaces. I can see the aggregated traffic fine but not at the sub interface level.

I don't have the same problem on my older Cisco h/w

Would appreciate any feedback on how to troubleshoot.

Mal