Strange audio export behaviour in 16.2.3

Just discovered a strange behaviour which I haven't seen before upgrading to 16.2.3

I noticed my latest exported video was in mono. On investigation, exporting 1920 x 818 timeline with stereo audio in mp4 / H264 only gives me the option of AAC in mono. Exporting same timeline as quicktime / H264 gives me the expected LPCM audio options (in stereo). Using the Youtube / Vimeo presets gives me the option of LPCM but won't play in VLC or Windows Media player.

I'm pretty sure my exports of mp4 / H264 gave me stereo LPCM audio options before the update, so not sure what's going on.

OS: Win 10

Restarting Resolve didn't change this, but restarting PC has brought back the expected audio options (LPCM etc).

Not sure why this is! But something to be aware of if anyone closes and reopens Resolve without restarting their Windows PC.

Hi - me again. Still getting this problem, even sometimes when Windows restarts. I don't understand what 's happening!

Selecting MP4/h264 only gives a choice of AAC. Using Quicktime/h264 gives the choices of Linear PCM, IEEE Float, and AAC. As I only use the Quicktime option I haven't had a problem with an AAC track coming out as mono.

Make sure Output Track 1 is set to Main 1 (Stereo).