numOutChannels is (value), it is not recommended that the usacElementType sequence contains (value) channels
ISO IEC 23003-3 (USAC):numOutChannels: Not forbidden but it may leads to playback issues with some players due to uncommon value for this usacElementType sequence
ISO IEC 23003-3:
Fix the encoder to fill numOutChannels with the correct count of channels computed from the usacElementType sequence, then reencode the content.