In a statement made to The Verge, Facebook has since confirmed that they are aware of the bug and that they are working to address it ASAP. The statement reads, “Some people are seeing older messages on Facebook.com. We are aware of the issue and are actively working to resolve it in as soon as possible. We apologize for the inconvenience.”
Not everyone is affected by this bug and it is unclear how widespread the issue might be, but regardless of how big a problem it is, we imagine that it might be awkward and a little embarrassing to suddenly see some of your old messages reappear out of nowhere. Plus there are some who would rather certain conversations not resurface, such as conversations with a former partner, or friend or family member that might have passed away.
No word on when the fix is expected to roll out but we’ll keep an eye out for more details if there are any to be had.