The train is using a week counter internally that overflowed. 17.11.2003 is exactly 1024 (2^(10)) weeks ago.
But this would mean the epoch here would be the 2 April 1984 or maybe the 1st, if you respect the time as well, which sounds a tiny bit random lol. But so would be to use a week counter in the first place :D Especially since those trains are from the early 2000s.
EDIT: Other times in 2003 are also possible apparently https://twitter.com/TAltgeld/status/1646386165006716928?ref_src=twsrc^tfw|twcamp^tweetembed|twterm^1646386165006716928|twgr^99a8805bbdf28d116a3a7037dc24347da978e819|twcon^s1_c10&ref_url=https%3A%2F%2Fwww.kreiszeitung.de%2Flokales%2Fbremen%2Fsorgt-fuer-spott-im-netz-geniale-loesung-der-db-der-zug-aus-der-vergangenheit-92212981.html
How did you get to that epoch? I haven't seen any images of this happening earlier than 2003, so the overflow must have happened late last year or early this year, and whatever week 0 is is some time around 2002/2003. That would also fit with your comment that they were introduced in the early 2000s.
Maybe they just didn't expect the trains to last 20 years 😄
God I would love it if I was suddenly transported back to 2003 as my current self.
Deutsche Bahn making up 20 years of delays in one go. Now that's efficiency
I love German regional trains. This is a very common issue. Happens all the time.
