Help with new to me 629-6 Talo 3"

[Azav8or]

I recently purchased this and am now having an issue. In single action once the hammer is cocked to the rear if I lightly touch the hammer or trigger, the hammer will move (jerk) forward slightly. after which it will procede normally when the trigger is pulled. Backing out the strain screw to a point, it no longer does this. Have any of you experienced this? Thanks.