I was investigating something strange on my planned route along the A61 in Germany and found quite a problem. There seems to be a discontinuity around the Kruft Kretz junction. The route is unable to cross the junction and so has to go off the autobahn; along some side roads, and then back onto the autobahn in order to continue. See the screen shot. Although I have put the start and end points of the route close together, this does change the effect. -So the problem is not caused by being too close to the junction and hence on the slip roads. As you can see on the screen shot, when the route goes back onto the autobahn, it actually goes in the wrong direction to start with!
BTW, I had hoped to upload two screen shots, but while the ‘Create New Topic’ seems to allow more than one file, it is actually limited to one 🙁
The routing on OSM gives the expected result. (see attachement 1).
There was a correction 4 months ago (see attachement 2), which probably relates to your problem. But I think this change should be in PE, and more importantly, since PE uses MapQuestOpen for routing, I would expect that the problem should be corrected there too …