Well after the September release some people reported they have issues with CEC (must have been a specific kind of setup as none of us could replicate it) this was mainly discussed in this thread
But I doubt this CEC update would have any influence on your audio volume. You might want to give more details on how you have configured audio and e.g. if pass-through formats are differently impacted that non pass-through. Also have you checked that the Kodi volume is up at 100%?