Sorry for your exporting problems, but could you explain in more detail your exporting method. Are you exporting quicktime conversion? quicktime movie? And then from there are you having issues with after compressor or is this right from FCP?
I only have the problem when I export a quicktime. If I use quicktime conversion, I never have the issue. The obvious answer would be to export using quicktime conversion every time. The reason I can't is I work in news and sometimes I am up against a deadline that is too tight to wait for the long export time that comes with quicktime conversion.