Looks as if the 2nd half of the concert that night had reversed channels, even though the first half was fine after rebooting - it seems as if the reversed channel returned.
The line-out to my R-09 was fine for both halves. So I think it is my MT, which has the channel problem. Don't know if anyone here experience reverse channels on the MT from a V3 using the current firmware and 8GB Kingston 45X card recording at 24/96 via coax.