In v3.8, we changed the MIDI clock implementation such that, any incoming MIDI Clock will set the internal clock in the controller and then it starts generating its own MIDI Clock. This works better for a number of functions, but we had some feedback that syncing loopers like the Chase Bliss Blooper to Ableton MIDI Clock with this feature leads to the Blooper drifting after a few cycles.
I sent a user a custom firmware which passes MIDI Clock thru directly and he has confirmed that it works without issue. We switched away from this because the MIDI Clock might drift when the controller is executing other functions (for example, banking up or down will cause the MIDI clock to deviate for a short time), but it seems to works fine with the Blooper and Ditto x4.
We’ll add this as a user selectable parameter in the next update. For now, if anyone needs this, we can prepare a custom firmware which hardcode the MIDI Thru for MIDI Clock messages.