If the engine in my car runs fine on whatever gas for 10 years, but when I put the same gas in the tank 50 tank-fuls in a row and suddenly the engine turns into

If the engine in my car runs fine on whatever gas for 10 years, but when I put the same gas in the tank 50 tank-fuls in a row and suddenly the engine turns into a pink flamingo, yes it is defective. If my LCD monitor displays any image I want, but when I try to show an image of a checkerboard it loses sync with the incoming signal, yes it is defective. (There were a number of similar problems in the telephone network around the introduction of T1 signaling, and it's why the 1000Hz milliwatt test tone was changed to 1004Hz.) These things were never acceptable.