I have a KN1400 but am new to this and aspiring for the KN7K :-) Played accordion for 20 years from age 10, then the demands of working in the computer industry cut severely into practice time for 20 years, now am picking it back up.

I tried this out in Pianist mode and the display is AsM79 which is correct. If you take out the Bflat key you have an AflatMajorSeventh displayed as AsMaj7 so when the 9th is added in I guess the display folds up the Maj to just M.

In fingered mode I get As add 9 and in one finger mode which would be bogus regardless it shows es min 7