It's not a defect if combining two channels is making it a bit louder. Just use the Mixer settings. If the Mixer is set to 50/50, you can adjust the combined channels volume, louder or quieter. If the Mixer is set to 100/100, you can only go quieter.
No. I am talking about the pure fact of setting an empy divider to dual mode. I have no blocks enabled in the chain. Everything is disabled. Just ny getting am empty divider and set it to dual. It already increases the signal. Nothing there