Watch Bjorn's videos and you'll see that it certainly isn't confined to Tesla. Newer models have heated charge ports. With older vehicles, preconditioning the cabin for ~30 minutes supposedly helps.
Interesting. I live in a similar climate with fluctuating temperatures and I haven't had this issue but maybe the charge port on my PHEV is heated and I didn't realize. I have had the problem though where sometimes the charge port door is frozen shut during cold temperatures.