About 5 minutes after walking into High Isle, Bastion attacked a guard (with no provocation) and got me a bounty. A friend playing earlier had Isobel do the same. Neither of us were anywhere near combat, just standing around with our companions.
Did you happen to be in Castle Navire? If so, there's an open issue where some NPCs will unintentionally cause you to get bounty which we'll be fixing in a future patch.
@allochthons Thanks for reaching out. Has this happened more than once? If you are able to replicate, could you get a clip of this happening? This would better help detail this issue to the Dev team. Thanks!