Trying to output multiple audio tracks, but OBS puts all audio on 1 track

[corbu]

Hey everyone,

I'm trying to do something seemingly basic on a Mac.

• Record my screen, with system audio
• Record my laptop mic
• Output system audio to Track 1
• Output mic audio to Track 2

I'm recording to MKV, have tracks 1 and 2 enabled in Settings, and have the tracks assigned/checked in Advanced Audio Properties.
When I view the output file (either the MKV in VLC Player, or the remuxed mp4 in Premiere), all of the audio is on the 2nd track.

I've tried multiple track configurations. I've walked through this with ChatGPT and showed it my log files, and it can't find a problem with my settings.
Does anyone have any ideas as to what might solve this?