It's most likely the trigger bar spring rubbing or perhaps rubbing on the access panel.
It will probably cure itself given time but if your not patient, (I'm not patient at all) you might be able to pull that panel.
I can never remember what that torx size is 6 maybe, tiny little bugger.
Then you might be able to clean up any rough spots on the trigger bar, you'll be able to see the spring and how it coordinates with the bar.
A dab of grease after smoothing also helps.
Be careful retightening the screw on the panel. Just snug, don't want to strip out the polymer.
In Memory of Paul "Dietrich" Stines.
Dad: Say something nice to your cousin Shirley
Dietrich: For a fat girl you sure don't sweat much.
Cue sound of Head slap.
RIP Muggsy & TMan
"If you are a warrior legally authorized to carry a weapon and you step outside without that weapon, then you become a sheep, pretending that JOCKO will not come today."