If you see this, DO NOT CLICK POST TO MIIVERSE. It seems to temporarily corrupt the friend list data in the console's memory until you reboot the console and this can lead to the friends list crashing when opened, causing you to lose unsaved progress in NSMBU.
oh my bro i was about to post it till i saw your post!
Yea, I've noticed the game acting weird when hitting that. Hopefully it gets fixed soon!
also pretty sure this applies to Luigi U as well
i disabled miiverse in nsmbu
Should've read that warning before doing just that... oh well.
a) this should not be happening as a result of no community and is indicative of something else. i could not reproduce b) either way, this should be resolved now that the appropriate communities exist <3