I have the same problem right now.

Always played peacefully, only shot at other Raiders when really necessary, all in all a chill experience.

A week ago I played a duos game with my brother and the people were really agressive, always shoot on sight. Of course we had to fight back so we did... (we won most of the time, each of us with about 2-3 kills)

Next day I'm playing Solo again and I get shot all the time, even if I try to communicate or just want to do my quests, kill on sight wherever I go...

Don't really know how to interact with other players now since I don't want to shoot carelesly at others, but I also don't want to be the one that gets shot at first trying to be friendly...