Your npcs need to target the BP_AI_Target for right now, in the future they will be targeting the dummy mover. Is that how you have them set up?

If you have them targeting the player actor (which is how most targeting is done in Unreal due to how they have the AI blueprints set up) they will shoot at the center of the roomscale playspace because that is were the "Player Actor" technically is. This could be to left or right of you depending on where you are standing.

This is where Epic's definition of "actor" and roomscale VR don't exactly mesh up. To fix this we need to spawn a targeting actor (in my examples the BP_AI_Target) and move it along with the camera's position in the roomscale playspace (The player's position). This is done by default with Weapon Masters character.

If you go into the BP_AI_Target you can turn on it's sphere collision components visibility to make sure it is following you correctly. This can be helpful in debugging the issue. At this point your AI just need to know that they should be looking for this AI_Target actor and not the player actor. Make sure to show your AI's attack line traces so you can see where they are trying to aim (also great for debugging). Once we figure out what they are aiming at it will be easier to see what the issue is.

Are you using your own AI or an asset AI? When I get home today I can show you where in the zombie AI I set the Target they are looking for, maybe this will be similar with your AI and an easy fix!