This evening my phone was reporting the wrong date: Feb 24 2002. That led me to the following post: https://us.community.samsung.com/t5/Galaxy-S-Phones/Date-keeps-changing-randomly/td-p/1092319 (which I can't reply to for some reason) in which someone suggested it could be a GPS thing.
Indeed, Feb 24 2002 and Oct 10 2021 are both GPS week 131 day 0, but with different GPS epochs. ( http://navigationservices.agi.com/GNSSWeb/ )
I don't know if it's worth mentioning, but after I toggled "automatically set date and time" on and off in settings to force my phone to reset the time from the internet, the blue light filter turned off as if it were daytime, and I had to reset it as well. (the time was correct, though, at around 11 pm, so I wonder if the blue light filter app had the wrong location?)
Are there any logs I could access from ADB that might give more information? My phone is running software version G950USQU8DUD3, which is the most recent version according to the update checker.
I suggest you don't mess with your own phone, unless you don't mind samsung rejecting your issue cases since you started messing with the phone on your own.
So, instead you should submit error report to Samsung Members after reproducing issue (or just.. toggle the auto set date and time few times).