Nothing may blow up, but it definitely irks the shippers.
Mainly because these kind of developments mean that the main character are typically too enamored by their first crush/NT soulmate/etc that they ignore the other girl for XX amount of episodes, until the other girl reappears only to die tragically
... And then suddenly the main character suddenly cares about the other girl.
Plus with AGE being a generational story... I wouldn't be surprised if XX number of episodes = 10+ years.