If the listener position has an effect on behaviour, the audio of the event must be being attenuated based on distance. This means that the event is 3D, not 2D. There are three possible causes of this kind of attenuation.
The first is an effect that applies spatialization. Can you confirm that there’s no spatializer effect, object spatializer effect, or similar effect on any of the event’s tracks, or on any of the tracks of the events that event references?
The second is spatialization applied to the single, multi, and programmer instruments in the playlist of a scatterer instrument. As mentioned above, this spatialization is not applied if the scatterer instrument’s Min & Max Scatter Distance are both set to 0.
The third is attenuation due to a volume property being automated on a distance built-in parameter. Do any parameters appear in the transport bar of your event? And if they do, are they based on distance?