What do you have them targeting?
If they are targeting the actor (BP_VRCharacter) then they will shoot at the center of the play space (this is counter intuitive I know but its how AI works if you are using Epics built in AI logic). This is the exact reason why the BP_AI_Target exits. Its an actor that follows the player around the play space that the AI can target correctly. In the future AI will target BP_VRDummyMover and I will be removing BP_AI_Target. You can have your AI target the BP_VRDummyMover by passing it to them as the actor to follow/attack.
Does this makes sense?