A simple test wich I can reproduce:
*Put the Virus in seq. mode
*Select RAM-B1 ARCTIS HS on channel 1
*Perform Store->Dump Arrangement
*Play back the sound (without reading back the dumped sysex). The Virus now only plays on the left output channel (I use output channel 1). I have to power it of to get it back in "stereo". putting it in "sleep mode" is not sufficient. I really have to take the power cable of to get it working normal again.