upgrading current -> graphics bug

hello,

i've been using -current for awhile. lately when i try to upgrade, i see 
this screenshot after i type "shutdown now": https://i.imgur.com/58aOGnG.jpg
from then on the system is unresponsive. to complete the upgrade i 
hard-reboot and jump into single user mode to finish the upgrade process.

i'm following the instructions from 
https://www.freebsd.org/doc/en/books/handbook/makeworld.html

it's been like this for awhile (a couple of months). it might be caused 
by the new vt terminal driver? i'm not sure. let me know if you need 
more information on how to reproduce this.

greetings,
david