I have a midi accordion attached to the Audya AjamSonic.
Everything is perfect except for the starting of some of the Styles.
Of the Ballad Styles over half of them won't start on the first press of the bass button.
With 'Key Start' on, I press the 'Bass' button once and the style won't start, If I press it once more the style will start OK, then after that the Style starts perfect on first press of the "Bass" button.
This happens on all of the Styles from Ballad to Ballroom.
If I press the Major/min/7th/dim button on the accordion first, all Styles start perfectly first time.
Somewhere in the setup the accordion bass button row is not getting the message to start on the bass button first time as it does on the chord button.

Just a guess here... If the Audya's style engine requires a CHORD (i.e., 3 notes) to be received to start the accompaniment, a single note on the bass channel isn't sufficient.

There are Easy modes where a single note is recognized as a major chord. It could be the styles that work are memorized with Easy mode.

The bass button should be set to a different channel so it doesn't start the accompaniment, the chord button should be the one starting the accompaniment so you get the miner, seventh, etc.