I have seen some adjustable triggers give those kind of problems at times. Most men look to the bolt, spring and firing pins but at times the problem is snow having melted and leaked into the triggers and turned back to ice. If the sear piece is allowed to move some but not enough the cocking piece drags on it and slows down causing light strikes. If the rifle is left in the fired position with some of them the sear piece can freeze in the downward position and then the rifle will not cock at all. Or ice can fill the space in-between the coils of a springs and not allow the parts to work because the spring is now braced and can't compress, or may simply not expand out more with full force.
All of the after-market adjustable triggers can be made to have cleaner breaks and many can be adjusted to have lighter breaks then Mr. Mauser's original Military triggers, BUT when worked over to a good break and set to have no back-lash and a short 1st stage, the old 2 stage military triggers are (and probably always will be) the most reliable ones ever made.
If you have an adjustable trigger installed on a Mauser it can be a good idea to take the action out of the stock and when warm give it some blasts with carburetor cleaner to get all the oil and all the water out. Blow it dry with a compressor or even a can of compressed air like they sell at computer store and put it back in 100% dry, or do what I have done and use automimic transmission fluid as a cold weather lube. Ice will grab to clean steel but steel lubed with ATF is hard for ice to hold onto well. It gets chipped off much easier then dry steel.
The coldest temps I have ever hunted in were about -45 F and in the cases where I did use adjustable triggers cleaned and lightly lubed (and with air blown through to remove all excess lube) I have not had any problems. My old 338, my 375H&H and both my Mauser 270s and my 25-06 all have adjustable triggers in them, but I have never had such a problem as you described. However I have seen such things a number of times with other hunters and their rifles and triggers, and as a gunsmith I bet I have had 20 come to me asking me to fix their guns only to find they worked just fine by the time they got them to my shop.
In nearly all cases it's a matter of too much of the wrong lube (or grease) or ice blocking the guts from moving well. In some case I have been able to blow water out of the triggers in my shop. It's water in my shop, but out when they were hunting at -15 to -40 I guarantee it was ice.
Getting snow around the bolt and then operating it a few times drags some snow over the rear tang, and gets it over the sear on the trigger. Let that get warm in a truck or car, tent or cabin one time and it flows into the trigger. Then take the rifle out again and you can have a problem.
That's the reason I do recommend a light coat of AFT on the trigger guts. Dry steel and ice bond easily and hard. But you can push on a frozen drop of water on ATF lubed steel ---and it pops off easily.
As for me personally I have built most of the guns I now own with re-worked military triggers for this very reason. #1 using the old triggers allows for a smaller mortis in the inletting so that makes for a stronger stock to take recoil and #2 by installing an over-travel pin inside the coil spring I can eliminate almost all backlash.(leaving about .005" is all) Stone the cocking piece face and the sear to proper angles and set the front foot of the trigger to give only about 1/8 of 1st stage and I get a good 3 pound trigger that breaks clean. Not as good as the target triggers but still very good and extremely reliable. Such a trigger is plenty good for all shooting with a possible exception of actual bench rest competition and yet it's the stuff of legend when it comes to reliability.
Anyway.......food for thought.
I hope it was helpful.