Under the law, if it fires more than once, for a single trigger pull, for any reason, it's a machine gun.
However, if the cause is an obvious malfuction of the arm, prosecution is extremely rare. If the arm was modified to malfuction and fire more than once, that is, and has been a prosecutable offense. There are even reports of the Feds doing modifications to get an arm to fire more than once, to support a prosecution. I can't say its true, and I don't know it isn't, but there's been talk!
If you SxS fires both barrels at once, or your 1911A1 runs away at the range, its BROKEN, and the Feds don't normally care, so long as you stop using it and get it fixed.
On the other hand, if they feel you are intentionally using a malfuctioning weapon as a "machine gun", then you'll probably have your day in court.
Get the gun fixed.