Bug with DBO and Grand Master Level on Road Hog 4

When the grand master is at e.g. 100%, the first fader is occupied with for example a group master and I hit Pig+GM (DBO) to switch of all output and then hit Pig+GM again to switch everything back on, the grand master level then is always on the level of the first fader (a group master in this case) and not restored to his previous value (100% in this case)