I was swapping out a corroded copper tee under a 1950s slab house and used a push-fit fitting to save time. Thing blew off at 2am and flooded the crawl space with about 40 gallons before I could shut the main. Turns out the pipe had a tiny burr I didn't file down, so the o-ring never sealed right. Now I always run my finger over the cut end three times before I push anything on. Has anyone else had these fittings fail on old galvanized or copper?