snapshot causes kernel panic

I posted this to the forum at https://www.ixsystems.com/community/threads/snapshot-causes-kernel-panic.75700/ amd was suggested to make a bug report, so here we are.

FreeNAS-11.2-RELEASE-U1 (I know, it's not the latest, but I'm feeling a bit gun shy after the 11.2 data loss escapade.)

zpool get version shows a - for the value, so it's possible I'm not running the 'latest' pool version for the installed release.

I've been able to reproduce this multiple times. System is otherwise stable.

Once a snapshot is attempted, manually from the GUI or via a scheduled task, the system kernel panics and reboots.

This is what I was able to capture via remote console screen recording. The system will just be sitting there until the snapshot is attempted:

panic: solaris assert: zap_add(mos, desl_dataset_phys(ds)->ds_snapnames_zapobj, snapname, 8, 1, &dsobj, tx) == 0 (0x5 ==0x0), file: /freenas-releng-final/freenas/_BE/os/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c, line: 1534
cpuid = 3
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe0469cbc3d0
vpanic() at vpanic+0x177/frame 0xfffffe0469cbc430
panic() at panic+0x43/frame 0xfffffe0469cbc490
assfail3() at assfail3+0x2c/frame 0xfffffe0469cbc4b0
dsl_dataset_snapshot_sync_impl() at dsl_dataset_snapshot_sync_impl+0x628/frame 0xfffffe0469cbc560
dsl_dataset_snapshot_sync_impl() at dsl_dataset_snapshot_sync_impl+0f7/frame 0xfffffe0469cbc6c0
dsl_sync_task_sync() at dsl_sync_task_sync+0xae/frame 0xfffffe0469cbc6f0
dsl_pool_sync() at dsl_sync_task_sync+0x3b/frame 0xfffffe0469cbc770
spa_sync() at spa_sync+0xad5/frame 0xfffffe0469cbc9a0
txg_sync_thread() at tgx_sync_thread+0x208/frame 0xfffffe0469cbcab0
fork_exit() at fork)exit+0x83/frame 0xfffffe0469cbcab0
fork_trampoline() at form_exit+0x83/frame 0xfffffe0469cbcab0
— trap 0, rip = 0, rsp = 0, rbp = 0 —
KDB: enter: panic
[ thread pid 15 tid 101395 ]
stopped at kdb_enter+0x3b: movq $0,kdb_why
db:0:kdb.enter.deafault> wrtie cn_mute 1
cn_mute 0 = 0,x1
db:0:kbd.enter.default> reset
cpu_reset: Restarting BSP
cpu_reset_proxy: Stopped CPU 3

Current system specs:

Supermicro X9SCL+-F

Xeon E3-1230

16 gig ECC

LSI 9211-8i

2x Crossflashed Dell H310

Firmware 20.00.07.00 on all three adapters (covers all available drive bays with an extra port on one of the cards)