Ah, you found the “full moon version”. A little easter egg depending on what the last day you played was ;P
ohhhhh I kept trying to recreate it by closing and reopening the game or trying to see if catching up on routes was the requirement when that didn't work, it being the day in game makes way more sense lmao
got curious and wanted to know exactly when the title changes and it seems like you just need to trigger the moon phase animation/day change to change the time on the title screen. I thought you just had to load a save from that moon but if it doesn't trigger the animation it seems like it stays whatever you left it on before you loaded that save. now I'm more curious so I'm gonna be checking what all the moon's change. it's always fun finding stuff when you think your done/caught up :3