well that didn't take long.
After giving the hatch latch assembly a good WD-40 soak a few days ago, the problem persists. After not having driven it for a few hours, I went to get something from the Vibe in the dark garage, and noticed the interior lights on. Yep, it was the hatch giving the door ajar signal again.
Somewhat frustrating...although lucky I guess that between the LED interior lights and run-down protection, at least she's never not started.
I guess I'll soak it again, but I'm not holding much hope that it will solve the issue.