Before the bloodtrail patch, i didnt experienced this, But now really often:
I just cant move my character to follow the cursor, the char is stuck in oviously free landscape: even using movement skill cant get me behind the invisible blockade.
Therefore I have to abort the mission. Even the camapign is unfixable broken for this cahracter (the Den that is done together with Ilthain wouldnt let me to the boss-encounter, because the "trail" didnt like that I ended the game after the waypoint and now doesnt provide me a new trail to trigger the script).

Guys, you should fix your game ultimately (and that very soon!). With new content you introduce new bugs. That would be okay for a short period of time, but what isnt, is that new bugs are introduced to the existing game that are this frustrating.