dvd/receiever multichannel in/output problem

GONZO HERE. Rotel rsx 1057 receiver sony dvp9100es dvd player. having a problem while adjusting speaker levels through the dvd player. when say for instance adjusting left surround speaker i here a pop in the right surround speaker every db the left speaker is adjusted up or down is this common or is there a problem. if so any suggestions. this is only in multi channel output mode no adjustments can be made inthe dvd player via digital output