I pulled the display assembly completely apart (and I mean completely), checked the caps on the inverter board (looked fine), reseated all cables, and booted it up again. Lines are now gone.

I noticed that when I thwacked the 'top' of the laptop the screen would lose picture, so I'm guessing a cable was loose or just needed to be moved.

Alas, that bottom bezel will never stay without tape again.

Hopefully, if it continues to behave, I'll take it to class tomorrow and see if I get any stares.