All of the backtraces in that are identical:
db:0:kdb.enter.default> bt
Tracing pid 26689 tid 100757 td 0xfffff80251dd5620
kdb_enter() at kdb_enter+0x3b/frame 0xfffffe046257aaa0
vpanic() at vpanic+0x19b/frame 0xfffffe046257ab00
panic() at panic+0x43/frame 0xfffffe046257ab60
trap_pfault() at trap_pfault/frame 0xfffffe046257abb0
trap_pfault() at trap_pfault+0x49/frame 0xfffffe046257ac10
trap() at trap+0x29d/frame 0xfffffe046257ad20
calltrap() at calltrap+0x8/frame 0xfffffe046257ad20
--- trap 0xc, rip = 0xffffffff80e9a6fa, rsp = 0xfffffe046257adf0, rbp = 0xfffffe046257ae00 ---
in_delayed_cksum() at in_delayed_cksum+0x5a/frame 0xfffffe046257ae00
pf_test() at pf_test+0x2493/frame 0xfffffe046257b010
pf_test() at pf_test+0x2088/frame 0xfffffe046257b220
pf_test() at pf_test+0x2088/frame 0xfffffe046257b430
pf_check_out() at pf_check_out+0x1d/frame 0xfffffe046257b450
pfil_run_hooks() at pfil_run_hooks+0x90/frame 0xfffffe046257b4e0
ip_output() at ip_output+0xa53/frame 0xfffffe046257b610
udp_send() at udp_send+0xa0c/frame 0xfffffe046257b6d0
sosend_dgram() at sosend_dgram+0x345/frame 0xfffffe046257b730
kern_sendit() at kern_sendit+0x1f9/frame 0xfffffe046257b7e0
sendit() at sendit+0x19e/frame 0xfffffe046257b830
sys_sendto() at sys_sendto+0x4d/frame 0xfffffe046257b880
amd64_syscall() at amd64_syscall+0xa86/frame 0xfffffe046257b9b0
fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe046257b9b0
--- syscall (133, FreeBSD ELF64, sys_sendto), rip = 0x801f929ea, rsp = 0x7fffdf5f84a8, rbp = 0x7fffdf5f84f0 ---
Fatal trap 12: page fault while in kernel mode
cpuid = 3; apic id = 03
fault virtual address = 0x18
fault code = supervisor read data, page not present
instruction pointer = 0x20:0xffffffff80e9a6fa
stack pointer = 0x28:0xfffffe0462267df0
frame pointer = 0x28:0xfffffe0462267e00
code segment = base 0x0, limit 0xfffff, type 0x1b
= DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags = interrupt enabled, resume, IOPL = 0
current process = 11651 (unbound)
trap number = 12
panic: page fault
cpuid = 3
KDB: enter: panic
I'm not seeing any similar backtraces for previous crashes when I search, but in_delayed_cksum at the top of that makes me suspect it may be an issue with checksum processing, but it could also be a hardware issue in general.
Maybe try toggling the hardware checksum option under System > Advanced, Networking tab