I think the bug was that it counted as "one mug of alcohol" on the floor, and the entire thing stuck to their fur, which wouldn't happen in real life.

One lick of alcohol soaked fur was the same amount of alcohol as a full tankard of beer. There was only one "unit" of alcohol. Hence dead cats.

Unintended behavior would be more accurate.

Maybe you don't realize just how much dwarves drink :v