This is extremely unsual, as already mentioned. Lots of ideas can be thrown out but if you have a camera to take some pics of the muzzle (assembled), then the slide inverted, plug, and broken spring, some people here can probably give you a much better idea than just guessing.
If you bought the gun used the first step is to replace the spring with a known good new one, 16lbs, from Colt or another major maker. The previous owner could have installed a far-out-spec spring or the wrong type. If you bought the gun new, there's no reason for it and Colt will sort it out.
A FLGR should definitely fix it, but it should not be happening in the first place and it's worth figuring out why.