[Dropped information - either people know or they won’t]
Re-re-re-checked it. It did not happen again. 
Tomorrow I’ll be able to play with others. Thanks!
Edit: OK, that was the sometimes not working ability of a mercenary that I only added to get him to level 10 - so I didn’t read what he will do in addition to his skills that I picked to reduce the time I have to use that NPC. So: no bug