You should not have to render before exporting a project either through the integrated or stand-alone version of AME. If you got a blue line in your footage, it must have been a bug in PP/AME. I've had errors exporting projects when using linked AE projects, so outputting bugs do exist.
Rendering is meant for smooth playback while editing (especially clips with a red bar. Any decent system will do fine with the yellow bars). Even if you do render everything before exporting, never use those render files in your output (i.e. make sure the 'Use Previews' box is UNchecked). I've done some tests and the image quality you get when using render files is inferior.
Hope this helps!
"I've done some tests and the image quality you get when using render files is inferior."
This is only because the default Preview file format is MPEG I frame, which renders very fast, but is not high quality. If you change it to Prores (macs only) or DNxHD, you will not have inferior file quality. But they will take longer to render.
Thanks for the clarification lasvideo!
Glad to help Pierre.
Thank you for the answers.
I 've read about the box "use preview.." and I think I 've never check it.
Anyway I wanted to be sure about renedering and now I am. Thank you so much!!!