I’m running Ableton Live (latest version) and have several devices connected to USB Midi (DSI OB-6 and Prophet 6, Moog Sub 37 and A4). In addition I have Octatrack and an Avalon Bassline slaving off of MIDI cables to AR (Octatrack directly from AR and Avalon through a daisy chain from AR to Octatrack to A4 to Avalon). The whole rig is also interconnected with MIDI cables and set up so that if the DAW is off, the AR is the master clock and sends clock and a start/stop signal to all devices (through a MIDI Solutions Thru box and daisy chaining . All devices that are able to receive USB MIDI are set to prefer it so that if Live is running, it’s supposed to be the master clock/start with the AR passing that information on to the two non-USB devices (Octatrack and Avalon).
In Live, I have Overbridge running on the A4 but not the AR.
What I have found is that (1) the system runs well in sync when no computer is connected and (2) all the gear pivots nicely when Live is on to sync to Live over USB, EXCEPT if USB sync is sent to the A4, the whole system locks onto 49bpm (regardless of the tempo in Live and, because everything is taking clock from Live or the AR which is taking clock from Live, regardless of tweaks to tempo knobs) and doesn’t respond to play/stop triggers from Live, If I am stuck at 49bpm and turn off USB clock sent to A4, occasionally this corrects with a big burst of digital noise followed by everything coming into sync with Live and occasionally it just stays stuck at 49bpm.
I basically have this issue sorted - I don’t send USB clock to A4 and it runs fine. But I’m passing on to the community at large in the off chance this is of use to Electron developers or someone else.