I don’t favor teflon tape, but it works and is preferred by a whole lot of people.
One thing is for sure. When applied it occurs to me if it is started one thread from the end of the male pipe fitting you would never have ended up with a situation like that. I would guess that problem is not an isolated one and is repeated all over the country in plumbing systems everywhere. I would guess further that as pieces of that work their way through the system and get lodged in valves that a lot of leaks and drips are not due to a faulty valve, but the misapplication of teflon tape. This applies to our air fittings as well and could go a long way to explaining why the coach will lean once or twice, and then never lean again. Could have been a little piece of tape that caused a leak and when it got blown out on the next cycle the Norgren “repaired ” itself.