When opening an old files with version 3195 (it supposed to be the latest), Glyphs adds parameters to the export tab like in the image, is it normal?
This should be fixed in the latest cutting edge release (3196).
That entry was always there but hidden. I fixed that by always showing everything and mark the debris with an exclamation mark. You can safely delete it.
In fact, I already did it without any problems. I was just pointing it out in case it could be useful