In the Trick Or Treat Function, hitting the left arrow brings me to Krin's page, then to my page, in a loop. Hitting the right arrow brings me to this page, then to my page, in a loop.

Yesterday, hitting the left arrow from my page brought me to Krin's page, before moving on to people I had not yet ToT-ed.

Generally, if you jump straight from your page to Krin's, then back (or your page, to the last active player, then back, depending on which arrow you used), it means that there is no one available to be trick or treated, aka you have already ToTed all active players within the last 6 hours.

If you're certain it's been more than 6 hours since you last ToTed and this is happening, though, then ignore me XP

That's probably what happened. I was at it for a while, and didn't even stop to think I'd get to the end.

Yeah, there aren't that many active players this year. The first full round I did, I think there were about 400 players for me to visit. My latest one I had about 230. Doesn't take all that long to do that many, honestly, so not surprised you didn't notice you'd done everyone lol.