In the latest build, when loading my game I had saved at July 1965 in devel-new c927fb2, date is shown as October 2050 and time is shown at about 6132:00:00. Otherwise the game seems to behave normally (the correct date and time still continues to show in the message centre).
Can you upload the saved game in which you hare having this trouble?
Here you go: https://www.dropbox.com/s/mu6k1qjbe26gxvx/Date%20and%20time.sve?dl=0
Thank you - found and fixed, I think. Do you care to re-test?
It's fixed.