While I've been testing it the only dsp that I have checked is Output Format. No resampling, 32bit, 5.1 channel, clone mixing and move to front are the settings for the dsp. It happens in clone or JRSS mode, if mixing is set to no up or downmixing it doesn't happen (obviously since move to front gets disabled automatically). Overflow handling is set to none and I can see 150% or more sometimes peak depending on the track, with clip protection on the peak tops at 100% but with quite tracks that should be no where near 100% they are amplified as well.
After the first track change with a format change and the problem happens the issue still occurs on every following track whether it's flac to flac or mp3 to mp3 until playback is stopped and restarted. Then flac to flac and mp3 to mp3 is fine until another mp3 to flac or flac to mp3 occurs.
I was looking for a way around the problem, as I really like some of the improvements to video playback in the last few builds, and thought I could uncheck move to front and just mute the center speaker. However MC doesn't retain that setting after restarting MC.