Sorry Stefan,
I have used Nexstars for a long time, but I can't answer your questions.
The only time I have had similar problems are either incorrect lat/long; incorrect time; incorrect time zone; manually accounting for daylight saving the wrong way; or having the tube on the mount the wrong way around.
From what you say, none of these are obvious.
Where abouts are you located? Perhaps someone could run though the procedure with you?
One small tip, I do every time:
After you get "Match Confirmed" Press Undo. It then tells you the three stars (pressing page down for each) that it thinks you aligned on.
Comparing what it thinks you aligned on, to what you thought you did, may go a long way to solve your mystery.
If it is only out a small amount, it could be your tube is not balanced properly (especially if using heavy diagonal/eyepieces). I also found that precisely levelling the mount made a big difference (even though it is not supposed to). Finally, using an illuminated reticle for aligning also significantly improved my scopes alignment accuracy.
These issues can be identified by doing your three star align, confirming what stars it aligned on, and then doing a GoTo one or several of those stars. If it is not returning precisely, check the balance etc.
But note, aligning using a light ep then switching to a heavy ep can itself cause alignment drift.
Hope this helps a little.
PS: Good luck with Uni
