Audio suddenly only one channel

[proben]

I use Zoom Workplace 6.2.3 on a Mac. My organization has cloud recording that is turned on for meetings.

I've reproduced this problem with 2 different computers using 3 different sound cards. When I'm in the meeting everything is fine, but the recorded video file only has sound in one channel. I'm not doing anything interesting with stereo imaging but it's annoying to have audio in one channel only when it was recorded in 2. I've double checked everything on my end - sound card, inputs etc and as I said it seems fine in the meeting and I have reproduced it on another sound card and even another laptop (all Macs tho; I don't have Windows to check). Is this a software bug being worked on? Or am I missing something obvious? Thanks.