The early GoldCup’s are prone to this with standard (non-target loads). The lightened slides and wide, heavy steel triggers prompted the sear depressor assembly to help eliminate trigger bounce.
I can’t remember when Colt stopped using the lightened slides (thought it was with the intro of the 70-Series), but regardless if someone has modified any part of the fire control group it will exacerbate the problem.
If so, replace with good parts including a new, factory Colt sear spring. The best thing is to replace the trigger with the newer aluminum part. Kings used to make them but they shuttered-up a few years back. The new GC’s come with them so they should be available for purchase.
Original, early sears configured for the depressor are difficult to find though later parts can be modified if necessary. The aluminum trigger will alleviate any need for the depressor assembly. If desired, a competent gunsmith should be able to modify and polish the 3-hole aluminum trigger to closely resemble the original.