I was exploring the fest zone and the window froze briefly like it does before the pet image loads. No pet, figured the site was being weird and just refreshed, and when I refreshed, one of my party pets had gone from 100% to 0% health. Hunger was at 8/10 so that's not it, and no battle occurred. Any idea what happened?

I'm assuming this happened right at midnight?

If so, it was indeed related to hunger. However, if the pet wasn't malnourished it shouldn't have fallen unconscious.

There's really nothing I can do at this time without more to go on. If it happens again, please let me know and maybe I can try to figure out what's causing it.