The Ozone 6.1 update added the new “Tube” mode to the Maximizer module.
Because of this, once Ozone 6.1 is installed, any Adobe Premiere session that was saved with an older version of Ozone 6 utilizing the IRC III Maximizer mode, will automatically open up with Tube mode engaged instead.
This will undoubtedly alter the sound of your final product, so you will want to go ahead and change this back to IRC III in most cases.
Once you re-save the session, everything will work as expected and this problem will no longer occur.
We do apologize for any inconvenience this may cause!