I'm having a similar problem. I normally play through a wireless transmitter/receiver which is plugged to my Stomp's L/Mono, but I still occasionally use a regular cable, e.g. when the transmitter is low on battery. The Stomp is integrated into a pedalboard, so there's always a cable plugged to the Stomp's Right input that is routed to a patch panel. Everything works more or less well except that amp blocks (just like other mono blocks in general) mix both input channels and that results in some gain loss because there's silence on the unused channel. It doesn't seem to be possible to solve this via the splitter and mixer blocks. Physically unplugging the Right input helps, of course.
It would be awesome if there was a way to configure the input block to use either the L/Mono or Right input, either globally or at a preset level.
