DSR-200 stereo audio captures as mono... sometimes.

This one's a mystery to me. Using an old Sony DSR-200, I shot footage typically using my left channel as wireless lav and right channel as an ambient mic... worked fine... captured fine. Then, set two people for an interview with lavs, one left, the other right. Recorded on the camera fine. That is, I've listened to the stereo tracks with headphones directly from the camera and both tracks are there as expected. HOWEVER, when attempting to capture this interview in PPro2, I get a mono clip with only the left channel!

Other clips captured (during the same batch capture) with both channels (stereo) fully intact. Any ideas?