Nothing is soloed and from headphones I can hear all the inputs and effects and faders which are in input channels. Effects connected to "main out"-channel can not be heard from headphones. Effects in main out channel (hi pass, 4comp, eq6, limiter) and master fader only audible from monitor speakers connected to main out xlr connectors.
Are you Rick sure effects in main out channel should be heard also from headphones? You own and use m20d? If so, my unit must be broken. Just got it one week ago.