Change Time zones cause ddb in 6.2 snapshot

snapshots/amd64/
Build date: 1506531075 - Wed Sep 27 16:51:15 UTC 2017

how to repeat the problem

# config -ef /bsd
[...]
Enter 'help' for information
ukc> timezone -480
timezone = -480, dst = 0
ukc> quit
Saving modified kernel.

reboot

wait boot ....
...
...
ddb>