Like S Keith predicted, the battery wasn't good enough to pass emissions. I got a CEL on my way to work Saturday morning.
But, what do you do when you have two hybrids that use the same battery modules (and both are having battery issues)? You take them both apart and swap all the Camry's good modules into the Prius' battery, of course! Batteries came out Saturday night, swapped the modules, put the Prius back together, went for a drive and got all the emissions tests to pass by 9pm Sunday. Took it in for emissions this morning and it passed.
Now I just have to get everything fixed so I can have 2 working cars again. Turns out one of the modules in the Camry's battery was leaking. The other modules all seem fine. I didn't even check the Prius' modules before swapping them out, so we'll have to see how many of them need replaced.