16 channel audio in MOV mixdown in Media Encoder

I am running the newest release of Media Encoder 2023 (23.0 build 57) on windows and I'm running into an audio mixdown issue when converting a video file. What I do is I take a 16 channel auido track .mov recording from a Blackmagic Hyperdeck and want to convert it to a H.264. Audio lives on channels 1 and 2 in the .mov and 3-16 are blank. In the previous version of Media Encoder (22.6.1 Build 2) the audio would mix down channels 1 and 2 to a stereo track. However when using the most recent version (23.0 build 57) channels 1 and 2 are being mixed down to just the left channel in the stereo mix. I went back to the previous version to export my video and got my expected stereo mix just now. Let me know if I am missing anything. Thanks.