Not trying to be that guy, but it's urea, which breaks down to ammonia due to microbial action once it's out of the cat. If a cat is pissing ammonia, it has big problems and needs to see a vet.

Other contributors to awful cat piss smell are mercaptans, the same compounds responsible for the scent of skunk spray, and pheromones and fatty acids released when the cat is spraying versus normal urination. It's all compounded by cats being adapted for arid environments so their urine is much more concentrated than human urine.

I love cats but they're gross little fuckers sometimes.

It's absolutely a thing, I've had several cats in my life look nearly on the brink of death before basically forcing them to drink or eat turned them around completely. They can be very stubborn. Fountains help a lot because in nature moving water is typically cleaner than standing water, so if your cat always refuses to drink, get a $10 cat fountain on Amazon, it works!

That makes sense, I wonder if it's the case and how common it is. I'll have to ask a vet tech that I know.

I'm under the impression that the basic product itself isn't a concentration, but more of a fermented brew.