Are you sure there isn't a second listener being activated on the debug camera? If you profile with Wwise (F6, connect to remote platform), you will see a second listener appear in the advanced profiler signal chain when you activate the debug camera if this is in fact the issue. 3-6 db does sound like it could be a second listener being activated. I am less familiar with Unreal, but in Unity the default setting adds a listener to every camera, so perhaps this is the case in Unreal as well? The volume being maintained after you deactivate doesnt quite fit this theory, but have you profiled with Wwise? You should be able to see what's adding that volume boost by looking at the signal chain. If you are using Wwise 2019, the Voice Inspector should help you here as well.