okay, listened again. at 1:01 there is a slight drop in the overall volume (piano and cymbals most notably). sounds like one of RVG's recording tricks to me. There's more of those, for example when the trumpet solo starts at 2:40, the volume of the piano and also that of the cymbals is slightly reduced again, with the latter slowly building back up again. Sounds okay to me, not truly annoying really.