Apple Weird text timestamp issue

[AceEvo55]

I have an iPhone 6, it's jailbroken, and yesterday I experienced the weirdest issue.

When you view the "list" of conversations in the messages app, each has a timestamp of the most recent message per thread. Usually it says "2 hours ago" or "2 days ago", or if it's old enough, "2015-09-09".

My issue, however, is that one of my threads has a timestamp of -310,207 seconds. Yes, negative. Adjusting my iPhone date to this coming Friday narrowed down the gap to "3 hours ago", and adjusting the time will get me as close as 2 seconds ago.
Needless to say, next Friday is not today. As we approach next Friday, the "timer" decreases, approaching 0. Originally, the timer was ~333,000 seconds, but now it is down to ~310,000, so I'm wondering what will happen when Friday actually comes.

That being said, I'm posting to see if anyone else has experienced this, and if so, please provide suggestions to fix it. I apologize if my post hasn't been clear enough, I'm quickly posting this during lecture! I can clarify or expand if need be.

Thanks, cheers!
Ace