Hi. I have read this thread and checked the mix parameter, it´s not the issue. But I noticed that this happens when both L+R inputs are used, when using L/Mono input only there is no gain drop. I use mono effects and I have splitted inputs L channel to electric and R channel to acoustic. Input A/B routing 100 -> L&R input, output pan 100 L&R, everything else I have used works fine but the delay gain drop. When I pull the right channel input out there is no gain drop.