http://prntscr.com/i2a6ia
I've never actually got that far in the game so far, so i havent had that much of a chance to be attacked near walled settlements, i remember the same thing happening in Radious which was 1 of the reasons why I switched, because i tought it was a feature of radious or base game
I also remember searching for it back then, but had no luck finding anything, if anyone could help me id appreciate it