I have an iMac running macOS Mojave.
A couple of times a day the time changes back to the 5th December 2013, 11 p.m.
When I go to System Preferences -> Date and Time and unlock the pane with my administrator password the time gets corrected.
I have tried to set the time zone both manually and automatic and tried all of the three Apple time servers.
Does anyone have an idea how to fix that?