Destination number missing in SIP URL on second outbound Invite

i did some testing on the the Trunk Sequence for Matched Routes, if the first trunk is not responding it to the invite message, the call is attempted through the second trunk, is this behavior something usual, because i was expecting this functionality to be provided by the Optional Destination on Congestion.

If I select my second trunk on Optional Destination on Congestion, the second outgoing invite message don’t have a destination number, therefore I am assuming the Optional Destination on Congestion, is itended for internal termination like playing a prompt or sending the invite to a local extension. If i select an extension number then call is received successfully? any ideas what this issue could be? Thanks

INVITE sip:x.x.x.x SIP/2.0
Via: SIP/2.0/UDP x.x.x.x:5060;branch=xxxxxxxx;rport
Max-Forwards: 70
From: “563” sip:[email protected];tag=xxxxx
To: sip:x.x.x.x – DESTINATION NUMBER MISSING BEFORE THE @ sign
Contact: sip:[email protected]:5060
Call-ID: [email protected]:5060
CSeq: 102 INVITE
User-Agent: FPBX-13.0.190.19(13.14.0)
Date: Wed, 08 Mar 2017 14:15:34 GMT
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH, MESSAGE
Supported: replaces, timer
Content-Type: application/sdp
Content-Length: 347