I think this is actually regarded as a 'feature' instead of a 'bug' per se.

Yamaha is in my estimation giving more control to the User when using any given Preset Style.

They're 'all' off so at least it's was done on a consistent basis.

When using the OTS link the Left part Voices are utilized, i.e. a Left part Voice bank is loaded, although it is left in the off position. Simply pressing the Left Part panel button will enable it.

Sometimes the Left Voice may not always be needed when playing a song using a Style. When a person is in any one of the given Variations within the Style, e.g. variation "B" etc. of A thru D, one can then enable the Left voice if he or she chooses by simply pressing the Left Voice panel button.

Granted, if a person changes to a different Variation within a Style the Left part Voice is once again disabled. But simply using the Freeze button as Gary mentioned will keep the Left Voice ON regardless of switching between variations.

This gives the User more control over the Style than for Yamaha to have enabled the Left part Voice(s) of the Preset Styles from the get-go on each and every Style in my opinion. >> You turn it ON when you want to, not the other way around where you turn it off when you don't want to, i.e. reaching up to turn it off when you didn't necessarily want it on in the first place. Doing that repeatedly could lead to aggravation needless to say.

In the case of switching to another Style either during a song or when starting a new song, simply turning off the Freeze function would allow the new Style to load its own new Left part Preset Voice (if any). You could then re-enable the Left part Voice and the Freeze function if you choose, to keep the Left part Voice always ON during the new song, etc. if you want it to be. If you switch between Styles "during" an existing song: then if you had left the Freeze button ON, the Left part Voice before you switched Styles would still be used and, if the Left part Voice panel button was ON on your Tyros at the time, it would still be active when you switched Styles of course.

Of course we all know - those who own a Tyros anyway , is if you set everything up in a Registration beforehand when using a Style for using with a song etc., then all your settings are pre-stored and called up when a person presses any of the 1-8 Registration panel buttons. Thus simplifying things even further. >> Once you get through the actual Registration setting up process that is.

Best regards,
Mike