This was fresh from PC start up and starting the MCC without doing anything else other than navigating down to the drum map section.
Around two weeks ago when I got my replacement KSP I did import a previously exported drum map though. I did not notice at the time whether the drum map was messed up or not.
I only noticed it now because I was trying to integrate the new drum machine.
I think this may be it. The importing of a previously exported session. I have never done that, so am not experiencing what you are. I do remember you had posts about importing previously exported configurations being all messed up, so I think this current problem, is likely another another byproduct, of that.
I do believe this is still a very big problem that needs to be fixed, but we need to narrow down the exact steps to reproduction and find out what the root cause is. As it stands now, it isn't a 'blanket' problem, that everyone will experience right out of the box. Only certain people will experience this, under certain circumstances and this is what will help the developers narrow down the problem, for a quicker, more efficient fix.
For what it is worth, I too have experienced other issues, with exporting and importing stuff via MCC, so it is definitely broken and not working right, I just have not experienced this exact issue.
Since you are experiencing the issue, try and do a factory reset of the unit and don't import any previously exported sessions/configs. Maybe even uninstall and reinstall MCC and see how that fares.
Thanks a lot for bringing these problems to everyone's attention. You are doing a great service for us all, in the long run.