Hello !
Actually my rut955 has no internet link (why: it is another story).
The date/time is 2021-01-10,23:05
No internet -> no ntp
In services > ntp i click on "sync with browser" and the system time is now correct.
If i reboot, the system time is once again 2021-01-10,23:05 !!!!
Does this behaviour correct for you ?