I noticed two more GPS route problems.
1. When route goes through the Hamburg junction south->north, it uses an auxiliary road instead of the main one. See the attached screenshot to see what I mean. The additional screenshot displays how it looks in real life (disregard the different route and truck position). You can see that going from south it's extremely hard to jump from the main road (to the left from my position): not only you have to cross prohibiting white lines, but with a trailer there's very little place to make a sharp Z-turn. Not to mention, you meet this dilemma at speed of ~80 km/h. When I first met this, I thought there was some obstacle dead ahead, that's why GPS suggested this deviation. Luckily, I was wrong, but I had a few unpleasant seconds.
BTW, on the cabin-view screenshot you can also see that when going from west, the route still uses auxiliary road, but at the same time requires frist to go to the left (to the main road), and then go back to the right.
2. Going out of the Felixstowe port, I took a longer path (to mark it explored). When GPS rerouted the path, it displayed a glitch at the roundabout: just like with west-north route at Hamburg, it recommends me to drive ro the right, and then suddenly turn left. Normally, roundabout left-turns (or right-turns in right-side driving countries) look smooth, without such deviations.