NAT Reflexive Rule uses wrong interface

Dear community,

i've configured a new XG firewall with two WAN links (one Active, one Backup).

The Active link is a fast VDSL and the Backup link is a SDSL connection.

Load balancing is working fine and is using the VDSL for all configured rules with WAN load balancing.

I host some services on the SDSL and have therefor created some NAT rules.

One of them is for VoIP and i want to have a reflexive rule for outgoing calls.

Problem is, that outgoing traffic is not using the correct WAN connection as per NAT rule destination address.

I can create a seperate rule for outgoing traffic and link it to the SDSL connection and this is working, but i was expection to get the same results for the reflexive rule.

Does this mean, that full 1:1-NAT is not possible in XG firewalls? Or am I missing something?

Thanks for any help