yes, KHS is right, I’m trying to put recordings which are already in mono onto mono tracks.
I used “export to Cubase” on my iPad Cubasis, and that is a special format file that Cubase then reads and creates a Cubase 9.5 project that matches the original Cubasis project (including with plugs and automation, etc.). So I have not imported any individual files. It might be that the files themselves have been converted to stereo upon the output.
I might just try bussing everything to a mono channel and hide the original tracks and see if I can mix that way. The real issues is that plug-ins are changing the stereo field in weird ways, moving the vocal left and right, etc. Quite confusing. (I’m new to Cubase so the moreso).