After upgrading today, I was unable to launch the terminal. Let me correct that -- the window would come up, but before any text was displayed it would close. I didn't see any error messages or logs or anything that indicated what the problem was.
Then I found bug #6892167. To verify if that was my problem, I went up to "Applications | Run Application" and did 'gnome-terminal -e /bin/bash'. It launched fine.
Confirmed, I followed the instructions in the workaround to the best of my ability. The "old" copy of the libvte I had was 9.6.0, but it still appears to work. Also, I was unable to unmount the old boot environment without forcing (-f) it.
All seems to work now.