For some reason, I suspect that a recording setting somewhere has been changed causing all rendered tracks to be saved in Mono Wave format irrespective of content. For years I have been able to use Render > Audio plus VSTi/DXi tracks to Stereo Wave file without a problem. This option now returns a Mono file exclusively.

I seem to remember some discussion previously about a panel which controlled mono or stereo recording but can find no reference to it.

Can anyone help???