I had my first talk to Maerwald and after that (he attacked me of course) in the upper left corner I saw the info that the quest Two Sided has ended unsuccessfully even though I didn't started it yet. It is strange for me to visit the city on the coast (where the quest Two Sided takes place) before talking to Mae. Why talking to him interrupts the quest? And going further, I should visit the city first and then talk to Maerwald?