hello,i don't know whether it is because of the map or it is because i saved the tour twice.I just finished a S2 from dessau to connewitz (southbound).I divided it into three parts to finish.i started the third part to finish it and i found that a BR182 is blocking the track at leipzig MDR,therefore it caused a traffic jam and 5 trains behind it were waiting for the green signal.And after my first and second part of the trip,everything is fine.Then in the third trip,the PZB didn't work.It only shows a B. Edit:it's in 2021 timetable
Saving a game can still cause random signal problems but I've also done several services without issues after loading. So just try again and it may be fine. If it still doesn't work, then unfortunately you'll have to try not to save.