There's 200+ late answers in the queue, I started looking at them and all the ones I saw were answered a while ago (a few months to a year). They're not recent at all and some were even upvoted many times already. It's interesting to note many answers seem valid as well
Any idea what's going on ?
It appears to have been a network-wide event, as expats also had a lot (percentage-wise). I presume it's a script that's identified a subset of answers on each site based on some criteria (some seem to contain question marks, for example?), and then they're being raised for re-review. It's quite a clever way really of cleaning up some old answers.
It's been discussed on meta.SE:
It would appear to be the result of a change in policy on what gets Late Answers sent to the review queue.
It used to be answers by users with a reputation of less than 10 after a certain time had elapsed on the question.
On 29th September the reputation threshold was raised to 50, meaning a lot more answers were destined for the queue.
