Why would they ship that out and risk the Colt reputation?
The pistol was fine. The problem was the magazine spring. Colt hasn't made magazines in-house in about 50 years, so they have little control over them. The vendors that supply them with magazines...at the time there were only three...don't make their own springs, and also rely on a vendor, who in turn relies on a vendor for the music wire that they use to wind the springs.
Spring load and tension can vary quite a bit from one spring to the next, even within the same lot...so it's inevitable that the occasional spring will fall to or below minimum specs after taking the initial set...which, depending on the wire alloy variation...can happen quickly.
All springs take an early set. Engineers take this into account, and rate the spring after that happens. e.g. A Wolff 11-pound magazine spring probably hits about 11.5 or more before the set, and averages 11 pounds after it occurs. Once that set is established, a good quality spring changes slowly.
Then, there's always the old axiom that's always in play: "Your equipment is brought to you courtesy of the lowest bidder."