I believe it's normal. When you retract the side the firing pin will return to its at rest safety position. Actually its very similar in the Glock. The firing pin safety plunger keeps it back until depressed. If you hold it down and shake the slide the firing pin should rattle back and forth. Release the plunger and it should not.
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."