Route VoIP Phones over specific WAN Connection Issue

[illizit]

Hello,

We currently have Pfsense, dual wan, two PPoE DSL Connections.
I have a LAN to WAN rule which routes the VoIP Phones (By IP Address) over a specific WAN interface (DSL #1). The issue is, if DSL #1 goes down, when it comes back up the phones will not register. There is no internet connectivity. I have left them alone for about 2 hours to see if the state table would reset however, they never seem to come back online until I manually reset the state table in pfsense.

Is there something I have setup incorrectly? Any advice?

Thanks