So I made a video a few weeks back to show the dealer next time I'm there. It was -14 C in the garage when I took it. Not touching the accelerator at all.
This morning it was -24 C in the garage (-32 C outside), and it did actually stall, but I was not recording it. Started right up again, and then I gave it some gas to keep it from stalling again. It leveled out after a minute or so.
It's going to be cold again tonight, so tomorrow morning I will make a point of taking another video. However, I'm pretty sure this could not be considered normal. My last N55 car never had this issue in even colder temps.