I have a similar problem, in that I normally record split track audio on my camcorder, its on-board mic into Ch1 and a radio mic onto ch2. Upon importing the files into Premiere, I use the Modify > Audio channels option to make the stereo track into two mono channels. And hey-presto, what previously peaked at 0dB now peaks at -3dB. Since I usually aim to peak any audio at circa -3 or -4 dB, this has not been a problem to me.
cool... looks like a bug