[not sure if this was posted before - if it was, please forgive me]
TL,DR : from Oct 24, 2021, some NTP servers could suffer a 19 years backwards time warp and go back in 2002.
This is due to a bug in the “gpsd” daemon. The bug resides in the gpsd_gpstime_resolv() function in gpsd v3.20 to v3.22. It will lead to the function providing a backward time of 1024 weeks (that is about 19 years) on 24 October 2021.
More info :
The bug is fixed in version 3.23 of gpsd that was released in early August.
Interesting background article here: