Some friendships last a lifetime, but so far Facebook has been a relatively recent acquaintance. Which makes it all the more surprising that the social network is congratulating users for being Facebook friends since 1969.

Many users woke up this morning to find that Facebook was congratulating them on 46 years of friendship, despite three major chronological concerns. 

The message has gone out to people who are younger than 46 years old, meaning the friendship would have preceded conception. 

The message would occasionally group friends into a single post, implying that dozens or hundreds of people became friends on the same day in 1969.

And the social network has only existed since 2004, so no matter how old the recipients of the distinction, they must have been preternaturally early adopters of the service. 

"We've identified this bug and the team's fixing it now so everyone can ring in 2016 feeling young again," a spokesperson for Facebook told The Verge.

While Facebook didn't explain the cause of the bug, many, including New York magazine and USA Today, have speculated that it's the result of the common Unix epoch glitch. 

Unix is an operating system used universally by internet servers and serves as the starting point of the Mac OS X system on Apple computers. 

Unix has a clock built into the system that keeps track of time by counting upward from midnight GMT on Jan. 1, 1970, a second at a time. This time system is known as the Unix epoch and it's used by devices that have a Unix or Unix-based operating system. 

GMT is five hours ahead of ET, so when people in North America saw the message, 46 years ago would have been Dec. 31, 1969.

The concept is similar to the Y2K problem, where computer clocks accidentally reset themselves because of the new year's date. The computer accidentally receives a Unix time count with either no value or a zero, so it resets time to the starting point. 

Most reports say there's little concern aside from an incongruous message on your Facebook timeline. The Facebook glitch should only be bothersome if you worry about your age, or work at Facebook.