This is really interesting, but also a little confusing - most spring materials shouldn't really lose much power in the cold until you get down below -30F ish. When they get really cold they can get a little stiffer, and actually contract a bit, and in really extreme low-temp they can get brittle. With some precision applications you can get material shrinkage around it and cause compression or binding, but that usually needs to be some seriously tight tolerances. At 10F though, they should be perfectly fine. Really curious what's going on here.
The first troubleshooting thing that comes to mind is either some cold lube getting into the mag from firing, or possibly some wax or other bullet coating doing the same. If that got onto the bearing surfaces of the follower or mag, it could gum things up enough to cause that kind of malfunction.
Another thought would be to see if there's any difference between exposed-lead bullets, vs a higher quality one with a copper wash, like Stingers or mini-mags. Different materials would have different friction inside the mag.
This is happening with all your mags? Fresh and old? Any chance it's an old mag that's been kept compressed a lot, or had a lot of cycles on it?
Regardless of what's going on, you might get some good benefit in swapping out the factory springs with extra-power mag springs like these:
https://tandemkross.com/green-springs-magazine-springs-for-ruger-mark-series-3-pack/