game clock (/age) appears to be slow by quite a bit

Maybe this has been brought up recently but I haven't be looking - or in the past and I can't remember.
Tonight I was getting close to another thousand hour mark and decided I'd take a screenshot for some reason. I checked the number of minutes /age showed before hitting it and looked at the clock so I'd know when to check again. Time came but /age was still short by a few minutes.

At any rate, I thought I'd look at it more closely so once all that business was done I started the stopwatch on my phone within a second of /age flipping a minute (checked clock also). After one hour on the stopwatch and clock the game age time said it had only been 48 minutes.
Has it always been this way? Have I thought that I've played for a certain number of hours while it's actually been a lot more? Obviously the game knows when a year has passed for birthdays, so maybe it's just something that doesn't display accurately all the time. /shrug

Im quite sure the server can out"clock" itself if you experience lag.