It's russian hybrid warfare against Germany. Since invasion of Ukraine there have been numerous cable cuttings on train tracks, several train derailments, some fires.
It has become so bad that police helicopters are regularly patrolling train routes at night to spot sabotage as early as possible. People complain about the flight noise at night which was not there before.
So as a person working in cyber security, I'd put this into the sabotage bucket.
It's not, it was a scheduled software update.