Duh, there are TWO things that highlight and say V1; one is “source patching for inserts and overwrites” and the other is “toggle the track targeting for this track.” It’s to the LEFT of the lock symbol. I had none of the former highlighted and so no video would load.
Having said that, now that I deactivate the one on the left, I can still load video onto that channel. I’m confused but, as long as it’s working, satisfied.
Thanks, though!