Tuning problem Shooting my impact MK2 today

Well I shot my MK2 compact 22 with my new helos gen2 6-24x56 I shot a mag and half not quite 2 mags but I was going in and out because it's was only 30 degrees it has a Huma bottle reg set to 150 sighted in at 30 yards and was amazed at accuracy and with the scope I just shoot pellets not slugs but I could see them going threw the same hole I couldn't believe that the glass was that clear on 24 power being a 600 dollar scope I'm running a carbon fiber sleeve and a peek spacer to tension the barrel also I was shooting marshmallows at 50 yards with second mag and noticed the pellets were getting lower and lower I found the Huma reg was down to 100 bar and it's set at 150 still had approximately 200 bar in the 480 bottle and thought I should be getting at least 3 mags using the 480 well the gun was outside the whole time and the Huma reg must have stuck from whatever lube was in it I guess because I brought it inside and about 10 mins it started to rise back up to 150 and I dry fired it several times it stayed there I thought it was weird unless there is just a small hole that would of froze shut or something it usually isn't outside that long when I shoot in the winter I'm usually in and out of a car or the house with the gun between shots to stay warm so it should be warmer to what is everyone's thoughts I think it was lube that got cold and stuck the reg shut does that make sense I don't know though it is pretty new and hasn't had to many shots threw it yet either any ideas ? Would Huma use lube inside it ? Other than that it was good fast to sight in up a few clicks and about 8to 10 to the left but I had some pretty good wind scope is mil mil ffp so the power changes shouldn't have changed the slight hold over I noticed changed drastically opinions of what happened would be great thanks 
 
I have a Huma on my Impact and three other guns with bottle regs on them. I’ve never exposed any of them to below freezing temps so I don’t know if any of them would act weird. Huma does use their own silicone oil on the belleville stack. We used silicone oil in the RC world because it was way more stable than conventional shock oils when it came to temperature changes. But with our guns we have to factor in high pressure air acting upon the lube. I hate tearing into a perfectly tuned gun but if you’re going to continually shoot in freezing temps, I would take the reg apart and wipe the components down. Then go with minimal lubing. Maybe they got a little overzealous at the factory with the lube.
 
I was hoping it would just work it's way out the gun won't be in freezing temps for that long a couple shots here and there and then back to the warmth it didn't do this until about 1 hour and 1/2 in that temp shot very well up to that point I'd hate to have to take it apart to clean out oil and risk air leaks exposure to the cold will be limited from here on out thanks