The latest firmware is 1.51A as opposed to the stated 1.50A so if you’re on 1.50 you could back up your projects and then update to see if you get any improvement?
Seems stable to me but, as with you, I haven’t spent any time documenting issues or adding them to the official thread.
Particularly with midiclock out, I’d test this with a variety of gear on both sides (ie digitakt to different gear than what seems late starting, and different clock to that same late starting gear) as I find elektron gear and digitakt specifically to be pretty steadfast in this capacity.
Where are you hearing the track volume drops? Right out of your headphones when using the machine standalone? Is it possible you’re pattern chaining and then manipulating parameters in real time so that the altered parameter is still impacted when returning back to that pattern?
Not positive what you mean about effects sends decreasing in input, are you saying the amount of the effect (example delay) that you dialed in, is reduced? If it was applied per pattern then it could be similar to what I described before, but in single patterns unless reloading, I don’t think it would be a problem.