Had this problem on my gun intermittently had it stripped down no problems found it was a gun I bought from new I had an old 725 which I used to lend to someone who came shooting with me every week so one week we swapped guns and it happened on the old one I was using which he had been using for about 2 years trouble free and my newish gun did not miss a beat so deduced it was me that was not releasing the trigger fully between shots.
They are not the best triggers you only need to hold on to the trigger a smidgeon and they stick when you go to fire second barrel got rid in the end.