..it was a very heavy trigger pull...it felt like the hand was still trying to rotate the cylinder after lock up.
Interesting observation. On the 432 that locked up I noticed the same thing. Occasionally the trigger would hit a "wall" after the cylinder locked, and it took additional pressure to get the hammer to drop.
The gun's price tag was hanging from a rubber band looped through the trigger guard, so at the time I assumed the problem was caused by the rubber band becoming pinched behind the trigger.
Now I'm not so sure. Some folks claim S&W revised the lock work geometry for this run. If that is indeed true, it might need further revision. Or perhaps de-revision.