R2600: how to deal with vlans in tenant's partition's

We need to setup different VLANs in dedicated partitions/Route Domains (right now on r5600, but later also on r2600).
Therefor we created first the VLANs on F5OS and assigned them to the tenant.
Then these VLANs will correctly shown within the tenant, but by default in the Common partition.
Now we deleted the VLAN in Common, switched to the required partition and tried to recreate it there as well using the exact same name like in F5OS.
But then we get the ERROR: Unable to find interface object for configured trunk member 3.0
For your reference, we have two LAGs created in F5OS, one for heartbeat with interfaces 4.0 & 8.0 and another for user traffic with interfaces 3.0 & 7.0.
When creating the VLAN within the tenant we select the appropriate trunk-interface from the interface list.

As already mentioned in another post it might be related that the interfaces are not correctly shown within the tenand. At least nobody could answer if this is a "normal" behavior.

Within the trunk details the correct physical interfaces from F5OS will be displayed:

But on the Interface list they are missing:

That's why also the error message makes (theoretically) sense:
ERROR: Unable to find interface object for configured trunk member 3.0

Where is this coming from and how can this be fixed?
Thank you!

Regards,
Stefan :)