I didn't have the litter problem, but I added to the tracker, since in my only medium-sized Challenge zoo, with about 20 habitats I'd set ATPs for, the guests wound up just rubber-banding along a main pathway as they tried to get to one very distant ATP and then when that failed, tried getting to another. They literally would spend their entire zoo stay just sort of circling around that area of path trying to get to one or other ATP, with hunger/thirst/happiness deteriorating as they'd ONLY fulfill needs if they were practically on top of a facility when they gave up on one lecture. And it made my finances tank because no one was looking at or making donations to ANY exhibits also not on that main Twilight Zone crossroads area.
I don't remember this happening as such last week in my Franchise zoo, but it drove me absolutely batty and I shut down all ATP's today in this one.
Editing: Now that I think about it, I just somehow didn't notice this happening in all my previous zoos since getting back into the game, and this is likely why every single zoo I've tried has tanked and gone bankrupt after I get past about 15-20 ATP's- once I shut down the ATP's in my current zoo I instantly went from losing money to making money with no other changes made.