I sometimes see level meters displayed as in the picture below, after changing song. The extra orange usually disappears within a few seconds. This is with no MIDI driving any plugins, and only silence passing into audio inputs.
The borders lighting up indicate a clipped audio signal - my guess is this is related to the plugins in the rack generating some sort of signal on changing song.
If you can narrow this down to a particular plugin I’ll see if I can figure out why.