[WWWJD]

The OP hasn't responded back with any further details so it's hard to say....

I will say though that I've had a similar situation, but with a modified rifle. My 700 SPS has a Jewell trigger and now, a B&C A5 Medalist. When I first installed the B&C, there wasn't enough clearance for the safety arm on the trigger assembly for the safety to fully engage. The thumb lever "looked" right, but the arm was hanging on the stock. I had to relieve the stock a little with a dremel for proper clearances.

Prior to this trimming, the rifle would:
a) Not fully engage the sear. Firing pin would fall on bolt closure
b) If the sear did catch, the trigger could partially break with the partial safety engagement (which wasn't really engaged... just looked engaged)
c) If the trigger/sear had been pulled with partial safety engagement, the rifle would fire when the safety was pushed forward for fire. (just in testing.. I never did this with a loaded rifle... Lord no.)

So that being said, if the rifle has an aftermarket stock, aftermarket trigger, etc... double check all the internal clearances. Once I fixed this, the rifle can be beat, kicked, dropped and not fire unless I break the trigger as it should.