Pardini SP Malfunction

Tonight in practice I experienced my first malfunction with my Pardini SP. It began when I noticed after the last round the sear was not resetting as usual. Then it began failing to reset (cock) during a string, requiring me to maunually cock it. Feeding and ejection are fine. Initially I thought it was an ammo issue. I am using Eley Club. I tried the same ammo in my Volquartsen Scorpiion and it worked fine. The pistol is clean and sear has been greased. I did have one  case fail to eject that was swollen in the chamber. Gun has never been disassembled beyond field stripping. I have not adjusted the trigger in a long time. Has about 5k rounds through it.

Read the manual about trigger adjustments.  If you don't have a manual, Pilkguns has it here  TenP Files: Pardini SP/HP Trigger Adjustment - Pilkington Competition (pilkguns.com)

I know this one 
Take the grip off and the adjustment screw in the back looking at you turn counter clock wise 1/8 of a turn

My understanding is there should be a very slight play in the trigger before the start of the first stage. There is none. Will make small adjustments to that screw to see what happens. Have not had any problems during dry firing, and just recently started happening, which made me think it was an ammo issue. Does the Pardini trigger loose adjustment in the trigger over time? Thanks for the advice.

No slack?
Turn you pistol upside down and look at the stem that your trigger shoe mounts to. Sometimes it can come loose. It is adjustable forward and backwards. If it is too far back it can cause this

I turned the sear adjustment screw on the back of the pistol (CP) about a half turn counterclockwise. That seemed to allow a more positive engagement of the sear and hammer. also adjusted the screw at the trigger that allows some play between the disconnector and the ear of the sear. Have not had a chance to shoot it, but hope it does the trick. Just a bit puzzled as to why after all these rounds, that it would require adjustment. Will see what happens.

One thing Alex kept saying to me is 1/8 of and inch because it make a big amount of change!

Shot it today. Problem solved. Still don't know why it would require adjustment, when it was working fine. Screw has plenty of tension.

Maybe your sear and hammer engagement was at the very edge, enough that the small wear caused it to slip off. Kind of like when 1911 falls to half cocked after cycling. You needed to sit sear just a bit deeper on the hammer.  CP on the back adjusts exactly that, sear to hammer relation, not the tension. I know you meant to ask why would the screw get unscrewed, but maybe it was just the minute wear on sear or hammer that caused this.