So the important part there is:
db:0:kdb.enter.default> show pcpu
cpuid = 3
dynamic pcpu = 0xfffffe007f12e380
curthread = 0xfffff8020ef64740: pid 67417 tid 100250 "unbound"
curpcb = 0xfffff8020ef64ce0
fpcurthread = 0xfffff8020ef64740: pid 67417 "unbound"
idlethread = 0xfffff80004340740: tid 100006 "idle: cpu3"
curpmap = 0xfffff8020e6cc138
tssp = 0xffffffff83717758
commontssp = 0xffffffff83717758
rsp0 = 0xfffffe004d5b6cc0
kcr3 = 0xffffffffffffffff
ucr3 = 0xffffffffffffffff
scr3 = 0x0
gs32p = 0xffffffff8371df70
ldt = 0xffffffff8371dfb0
tss = 0xffffffff8371dfa0
tlb gen = 589816
curvnet = 0xfffff8000408ba80
db:0:kdb.enter.default> bt
Tracing pid 67417 tid 100250 td 0xfffff8020ef64740
kdb_enter() at kdb_enter+0x37/frame 0xfffffe004d5b65b0
vpanic() at vpanic+0x197/frame 0xfffffe004d5b6600
panic() at panic+0x43/frame 0xfffffe004d5b6660
trap_fatal() at trap_fatal+0x391/frame 0xfffffe004d5b66c0
trap_pfault() at trap_pfault+0x4f/frame 0xfffffe004d5b6710
trap() at trap+0x286/frame 0xfffffe004d5b6820
calltrap() at calltrap+0x8/frame 0xfffffe004d5b6820
--- trap 0xc, rip = 0xffffffff80f712cc, rsp = 0xfffffe004d5b68f0, rbp = 0xfffffe004d5b6900 ---
in_pcbdetach() at in_pcbdetach+0x3c/frame 0xfffffe004d5b6900
udp_detach() at udp_detach+0x93/frame 0xfffffe004d5b6930
sofree() at sofree+0x245/frame 0xfffffe004d5b6960
soclose() at soclose+0x30d/frame 0xfffffe004d5b69c0
_fdrop() at _fdrop+0x1a/frame 0xfffffe004d5b69e0
closef() at closef+0x23e/frame 0xfffffe004d5b6a70
closefp() at closefp+0xa0/frame 0xfffffe004d5b6ac0
amd64_syscall() at amd64_syscall+0x387/frame 0xfffffe004d5b6bf0
fast_syscall_common() at fast_syscall_common+0xf8/frame 0xfffffe004d5b6bf0
--- syscall (6, FreeBSD ELF64, sys_close), rip = 0x800c8f47a, rsp = 0x7fffffffd978, rbp = 0x7fffffffd990 ---
The msgbuf.txt file in your redacted archive appears to be damaged, I can't check it.
That backtrace is not one I'm familiar with. It would be useful to compare that with the backtrace from other crashes. If it's close to identical it's probably a software issue. If it's a hardware problem they will be far more random.
Steve