[OpenSER-Users] The Via Header of CANCEL Message

[fancy]

According to RFC 3665 section 3.8 and RFC 3261 section 9,
there is only one via header in CANCEL message
(message F11, F13 at page 72 of RFC 3665).
But when I ran the similar scenario(through one proxy),
I got two via header in CANCEL message such as following:

CANCEL sip:UA12 at node11.under.test.com;transport=udp SIP/2.0
Record-Route: <sip:192.0.50.50;lr=on;ftag=11380>
Via: SIP/2.0/UDP ss.under.test.com;branch=z9hG4bKd068.25909417.0
Via: SIP/2.0/UDP 
node.under.test.com:5060;received=192.0.10.10;branch=z9hG4bKPUA4295483
Max-Forwards: 69
From: UA11 <sip:UA11 at under.test.com>;tag=11380
To: <sip:UA12 at under.test.com>
Call-ID: 11380 at tom.example.com
CSeq: 4 CANCEL
Content-Length: 0
P-hint: usrloc applied

How can I remove the 2nd via header?
Thank you

Best Regards,
Fangyu Ling