Trio, g moll, BWV 584

Yesterday I stumbled by accident on a recording of an organ trio in g minor, by Bach, I had never heard before, with the BWV number 584. I remember the excitement I felt in my youth when I heard an organ piece by Bach I had not heard before. And that's how I felt yesterday. In all those years playing and listening to organ music, I somehow never wondered what came between the Trio in d minor (BWV 583) and the Trio, after Fasch, in c minor (BWV 585). And it doesn't get played in concerts, otherwise I would have heard it long before yesterday.
The reason probably is that this Trio is very likely not by Bach. The musical substance is definitely by Bach. as it is based on the tenor aria from the cantata " Wo gehest du hin", BWV 166. The oboe part from this aria is the right hand part in this trio, and the basso continuo part has become the pedal part. The left hand part is completely new. The trio can be found in a manuscript that originates from long after Bach's death. Perhaps the scribe had access to a part of the original aria that has since been lost. Or perhaps he created it anew. Fact is that the oboe part is written in a way that allows it to create a secondary voice with the same material. For example, the left hand part enters in bar one, with material from bar 12 and onward of the original oboe part, transposed a fifth down.
As the left hand is probably not by Bach, I took the liberty to make some alterations. As the first bars of the left hand part are based on the right hand part from bar 12 and onward, it is strange that the left hand part in bar 12 and onward doesn't follow the right hand part from bar one and onward (yes, do read that sentance again... ). I took the liberty to 'correct' this. The original from the manuscript is indicate in a footnote.

Score available here: http://partitura.org/index.php/johann-sebastian-bach-trio-g-moll-bwv-584