Kernel panic in vmx/iflib

Since updating to TrueNAS-12.0-BETA, when I attempt to copy files to an SMB share, smbd unexpectedly exits, then the system freezes up due to a page fault resulting in a kernel panic and hard reset. I have been able to reproduce this exact behavior 3 times and it is consistent. Here is the tail of syslog before the system resets itself:

<118>Thu Jul  2 23:05:39 EDT 2020
<6>pid 2558 (smbd), jid 0, uid 0: exited on signal 6
<6>pid 2932 (smbd), jid 0, uid 0: exited on signal 6
<118>Jul  2 23:17:34 truenas syslog-ng[1659]: I/O error occurred while writing; fd='21', error='Connection refused (61)'
<118>Jul  2 23:19:34 truenas syslog-ng[1659]: I/O error occurred while writing; fd='5', error='Connection refused (61)'
<118>Jul  2 23:19:36 truenas 1 2020-07-02T23:19:36.373395-04:00 truenas.myers snmpd 2006 - - send response: Failure in sendto
<118>Jul  2 23:19:36 truenas 1 2020-07-02T23:19:36.373477-04:00 truenas.myers snmpd 2006 - -     -- SNMPv2-MIB::sysDescr.0
<118>Jul  2 23:19:36 truenas 1 2020-07-02T23:19:36.373495-04:00 truenas.myers snmpd 2006 - -     -- SNMPv2-MIB::sysObjectID.0
<118>Jul  2 23:19:36 truenas 1 2020-07-02T23:19:36.373542-04:00 truenas.myers snmpd 2006 - -     -- IF-MIB::ifPhysAddress.1
<118>Jul  2 23:19:37 truenas 1 2020-07-02T23:19:37.406636-04:00 truenas.myers snmpd 2006 - - send response: Failure in sendto
<118>Jul  2 23:19:37 truenas 1 2020-07-02T23:19:37.406701-04:00 truenas.myers snmpd 2006 - -     -- SNMPv2-MIB::sysDescr.0
<118>Jul  2 23:19:37 truenas 1 2020-07-02T23:19:37.406712-04:00 truenas.myers snmpd 2006 - -     -- SNMPv2-MIB::sysObjectID.0
<118>Jul  2 23:19:37 truenas 1 2020-07-02T23:19:37.406731-04:00 truenas.myers snmpd 2006 - -     -- IF-MIB::ifPhysAddress.1


Fatal trap 12: page fault while in kernel mode
cpuid = 13; apic id = 0d
fault virtual address    = 0x0
fault code        = supervisor write data, page not present
instruction pointer    = 0x20:0xffffffff80b936c2
stack pointer            = 0x28:0xfffffe0000589a10
frame pointer            = 0x28:0xfffffe0000589ae0
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        = 0 (if_io_tqg_13)
trap number        = 12
panic: page fault
cpuid = 13
time = 1593746390
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe00005896d0
vpanic() at vpanic+0x17b/frame 0xfffffe0000589720
panic() at panic+0x43/frame 0xfffffe0000589780
trap_fatal() at trap_fatal+0x391/frame 0xfffffe00005897e0
trap_pfault() at trap_pfault+0x4f/frame 0xfffffe0000589830
trap() at trap+0x286/frame 0xfffffe0000589940
calltrap() at calltrap+0x8/frame 0xfffffe0000589940
--- trap 0xc, rip = 0xffffffff80b936c2, rsp = 0xfffffe0000589a10, rbp = 0xfffffe0000589ae0 ---
iflib_rxeof() at iflib_rxeof+0x542/frame 0xfffffe0000589ae0
_task_fn_rx() at _task_fn_rx+0x43/frame 0xfffffe0000589b20
gtaskqueue_run_locked() at gtaskqueue_run_locked+0x121/frame 0xfffffe0000589b80
gtaskqueue_thread_loop() at gtaskqueue_thread_loop+0xb6/frame 0xfffffe0000589bb0
fork_exit() at fork_exit+0x7e/frame 0xfffffe0000589bf0
fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe0000589bf0
--- trap 0, rip = 0, rsp = 0, rbp = 0 ---
KDB: enter: panic