Cisco SCTP response packet from global instead of vrf


I’ve an interessting problem I’ve never saw before.

We have two Routers (19xx and 4451) with the same configuration design:

Dialer 1 and 1 LAN Interface in global table with default route over the LAN

Dialer 2 and 1 LAN Interface in vrf internet, default via dialer 2 towards the core.

The router is receiving a SCTP packet destined to the dialer 2 IP and sends a response packet not via the expected dialer 2 interface within the internet vrf where it was received, but sends it via the default route in global table…

Does anyone know why the response is send from another routing table?

The configuration is pretty basic without any leaking, just a global table for a vpn service and an internet vrf for an internet connection.

Thanks in Advance