Hi Choney,
It does appear that also on the style issue You are right on the mark.

Initial setting are memorised Okay but any subsequent changes to that style alters other settings at random.

On my previous test I only altered the parameters once and all was fine, it really does look look to be an OS problem.

I for one will be in contact with Yamaha for clarification

Many thanks for the video's and highlighting this issue.

Gilbert.