Actually just completed a run yesterday from Dresden to Leipzig and encountered no problems. My immediate suspicion would be a GPA speed trap.
Is there any indication on when all the broken services in journey mode on this route will be fixed? It's been months now since the route came out and we are still not able to simply even play all the content that we payed for...
Sadly DTG have a track record of not fixing broken Journey Mode elements. The G6 still has a shunting timetable that can’t be finished due to a signalling issue on RRO. So I wouldn’t hold your breath. The routes that came with TSW6 are already getting on for five months old and DTG are anxious to sell us the latest content, or Sodor, or Metro Rivals. So I wouldn’t hold your breath…
The only difference is that the original G6 journey on TSW2 supposedly worked when it came out but was broken when TSW3 came out. I have heard that it has been looked at and can't really be fixed (although that doesn't explain why that service is not simply removed from the journey). On the other hand, the Leipzig and 294 journeys have always been broken, even after DTG tried to fix the 294 journey once already. So I do have hope that these, at least, will eventually get fixed. The G6 is pretty hopeless though.