We then had a thought... what if the mice were also eating the dog food in the garage? The container lid for the dog food was not very strong (weak and flexible enough that a mouse could possibly squeeze in and out), and coincidentally, that dog food was also high in Vitamin K.
Once we got better sealed containers to store the dog food, it only took a few days before we started seeing delirious, sick mice running around aimlessly in plain day light. Shortly after that, we stopped seeing them entirely.
It's possible the dog food was not reversing the poison. Maybe with the dog food locked up they started eating more bait, or maybe it simply took longer than we expected for the poison kick in. But regardless, we definitely learned a valuable lesson about keeping the pet food well sealed!
In older houses it is nearly impossible to find all entries… they can climb, and will even enter through the roof.