Once I increased package memory the crash went away. 

 4(21729) DEBUG: <core> [parser/msg_parser.c:623]: SIP Request:
 4(21729) DEBUG: <core> [parser/msg_parser.c:625]:  method:  <MESSAGE>
 4(21729) DEBUG: <core> [parser/msg_parser.c:627]:  uri:     <sip:50.62.72.174:15060;transport=udp>
 4(21729) DEBUG: <core> [parser/msg_parser.c:629]:  version: <SIP/2.0>
 0(21722) ALERT: <core> [main.c:788]: child process 21729 exited by a signal 11
 0(21722) ALERT: <core> [main.c:791]: core was generated
 0(21722) INFO: <core> [main.c:803]: INFO: terminating due to SIGCHLD

(gdb) backtrace
#0  qm_detach_free (qm=0x2b7b70759010, size=64)
    at mem/q_malloc.c:269
#1  qm_malloc (qm=0x2b7b70759010, size=64)
    at mem/q_malloc.c:386
#2  0x0000000000560fa1 in parse_via (
    buffer=0x8c6a3b "SIP/2.0/UDP 50.62.72.174;branch=z9hG4bK3f84.7fd8a5e.0;i=3\r\nVia: SIP/2.0/TCP 75.43.10.221:60659;rport=60660;branch=z9hG4bKPjc9713006b62149648240ed4ea4686b85\r\nMax-Forwards: 16\r\nFrom: <sip:578626051@50.6"..., 
    end=0x8c6e7d "", vbody=0x2b7b7077ae90)
    at parser/parse_via.c:2540
#3  0x0000000000538e68 in get_hdr_field (
    buf=<value optimized out>, end=0x8c6e7d "", 
    hdr=0x2b7b707aa9c0) at parser/msg_parser.c:140
#4  0x0000000000539ac9 in parse_headers (msg=0x2b7b7079b100, 
    flags=2, next=<value optimized out>)
    at parser/msg_parser.c:351
#5  0x000000000053af8d in parse_msg (
    buf=<value optimized out>, len=<value optimized out>, 
    msg=0x2b7b7079b100) at parser/msg_parser.c:650
#6  0x000000000049a2ef in receive_msg (
    buf=0x8c6a00 "MESSAGE sip:50.62.72.174:15060;transport=udp SIP/2.0\r\nVia: SIP/2.0/UDP 50.62.72.174;branch=z9hG4bK3f84.7fd8a5e.0;i=3\r\nVia: SIP/2.0/TCP 75.43.10.221:60659;rport=60660;branch=z9hG4bKPjc9713006b621496482"..., len=1149, 
    rcv_info=0x7fff932d32e0) at receive.c:144
#7  0x0000000000528666 in udp_rcv_loop () at udp_server.c:557
#8  0x0000000000464daa in main_loop () at main.c:1638
#9  0x0000000000467adc in main (argc=<value optimized out>, 
    argv=<value optimized out>) at main.c:2566