Hi, I think this bug has been reported quite a few times. Some button combinations are buggy on some OTs. From what I read and understand, Elektron is working on resolving this via a firmware update (no time frame yet). I also have experienced other bugs on my MK2, and patiently awaiting that firmware update. You should also submit a support ticket for this.
For more info, you might want to check this thread:
I’m not sure if this is the same issue, but I have this with Func+Bank --> it is sometimes having weird behaviour, either not closing the window or closing it because I went to another menu but the other menu only gets active after second press. I have to see at home what exactly there was. Func+Arrangement I think didn’t trigger something else, but I think I remember some weird functionality now and then…
Well, I don’t know if you can get 1.40 firmware? But if it’s of any use that’s what I’m running on my MkII and it doesn’t have the issue or at least it hasn’t happened to me. And I’ve been using the arranger lately for linear recording and such.