My AVR i set up to upmix all audio to 5.1.2(top middle), but when the source audio is 5.1 none pathtrough, the number of channel are always set to 7.1. This makes my AVR think that there actually is 7.1 channels and upmix 7.1 instead of 5.1, and results in a very bad upmxi with almost no sound in the top speakers.
This bug has been around for a long time, so i hope someone soon can take the time try to fix this.