My game time traveled by itself to new years... The last time I played, I saved correctly, but when I went to play today it was new years. I don't ever time travel but 12 hours back or forward because I don't always get a chance to play during the day.
Luckily I didn't lose any villagers since I was at 8, but one is being forced in and I'm a little less than pleased.
Was the game console clock changed ( to change it go to system settings)? I am guessing you only tt using the ingame clock. The only time that happened to me was when I had to reseat the battery and the console clock reset itself to an earlier year.
That happened to me quite a lot on my old 3DS when it set my date back to New Year's in 2011. I did have a lot of problems with my previous 3DS when it came to things like that, so I assumed it was a system fault.
I'm just glad that nothing is set in stone until you load up your town so any time that happened, I quickly changed the date & time back to normal.
Do you know if it was only in your game that the time changed or your actual 3DS internal clock?