Like in the title. Near La Valett mansion in Novigrad I've interrupted some hunters trying to get rid of some drunks, fight started....I'm lvl 20, they are 34 but it's not the problem here... I killed them once, they got back as soon as I left the sewers in this area, tried to fight them again but during the fight now the are getting up with full hp! I had to run away from that area. And I'm not going back there until this thing is not fixed with the next patch or something.

Something similar happened to me after the Heart of the Woods quest in Skellige. The guy I killed at the end just keeps coming back.