Hi Mike,
When using the Soloist, if you generated a solo
before unchecking the "extra beat"option, the solo will have generated using that extra beat. Then, when you regenerate, it will correctly regenerate, but those notes are already there and so will always play.
The solution is to completely clear the Soloist track and start again. I just keep on repeating the process until I get what I want.
NOTE: If you have used a Realtrack Soloist and then saved the file, you will need to "UnFreeze" the Soloist track before you can do this. (Right-click on "Soloist".)

Let us know how you got on

Regards,
Noel