MIDI Sync Out USB

[losgatos]

Something strange happened and I don't quite get it, so I am hoping maybe someone here can explain it to me.

I've been using Audacity to record stuff from my MC-707 "for forever" as it were. I never had a problem. Until I attached my SYSTEM-1m via MIDI. Now whenever I tried to record, something was "way off" with the SYSTEM-1m getting really confused as to what the tempo is (the TEMPO SYNC is on for the SYSTEM-1m).

So today I decided to go through the various MIDI settings on the MC-707 and once I disabled "MIDI Sync Out USB" on the MC-707 the problem disappeared!

As far as I can gather the "official" purpose of that setting is to control whether the MC-707 sends out a MIDI clock over USB. That shouldn't have anything to do with the SYSTEM-1m which is connected via the regular MIDI port, should it? Anyone?