I'm with Jpyle on this.
It can get "adjusted" to the point that the trigger will not release the sear or the sear does release, but drags on the hammer.
Glad you corrected the gun, now correct your friend.
Friends should never play with another's unless asked.
"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
Life Member NRA
Life Member NAHC
Former President of the ECPT (Eifel Combat Pistol Team)