A niche issue, but if you have two switches utilizing the same account, the second switch needs internet connection to ping/verify to make sure that your account isn’t being played on more than one switch at the same time. This occurs when initially loading any game on the second switch regardless if the game itself is an online game and allegedly every few hours after that.
https://en.m.wikipedia.org/wiki/Tux_(mascot)
TIL, Linus Torvalds just likes penguins.