Sometimes on a revolver where it works fine,,then it's taken a part and put back together again,,then it doesn't work fine (like the trigger return)..
it can be as simple as the side plate is screwed down (too?) tight and jamming the trigger itself from smooth pivoting operation.
It can go un-noticed generally but when lightweight return spring is installed and the side plate is cranked down tight, the spring doesn't have the power to overcome any slight cramping the sidelate is placing on the trigger.
Back the sideplate screw(s) off just a bit (front one is the culprit generally) and all is well and the plate and screw positions are left as that. Revolver function and fires perfectly.
You take it apart, clean and/or work on it. Reassemble and replace the plate and screws and turn them a bit tighter. The result is a trigger that jams in return pivot motion with the light weight spring.
Not always the problem but can be.
Something else to check for.
Final fit is not the most precision in the S&W of today.
