[2022] Protean without having a gateway mission?!?!?

I have a quick question. Did anyone else encounter a protean in a hunt mission yet, becouse me and my mates did. Soooooo the mission was to kill 3 tormentors it was quit easy bug as we killed the 3rd one another target spawnt. We didn't thougt about it and looked for it. As my mate found it he just said it's smoke (one of the proteons). Neadless to say he annihilated us couse we werend prepared at all becouse we had no gateway as mission. He had no healthbar but was definetly there. I dont know if it was a bug but i need answers. Pls help if you know anything. Unfortunataly i dont have fotage becouse we werent recording but i have 2 mates to vouch for me.