That could be running on a remote time from a database, and it just had an error, or it could be pulling times from individual computers. So there's really no way to tell.
It's correct for me too (3 days, 15 hours, 20 minutes) and my clock is set "in the future" due to my timezone (it's Saturday 14:20 here). I don't know how the time is calculated but it's worth checking that your timezone is set correctly in System Preferences.
Given the number of MR viewers, it was inevitable that some of those clocks would have a bit of an extreme skew. Figure out the time from the server side?
This reminded me in an odd way about an announcement I once saw for Powerball or the other US mostly-national lottery: the fine print said that the cash value for a drawing was "only an estimate" -- implying that the large-pointsize annuity amount on the webpage was somehow more accurate. That seemed backwards to me.