problem to record audio from 2 sources web browser

[ChnokBabel]

Hi,

I use OBS Studio 30.0.2 64 bits on Mac OS.
In the same scene,i added 2 sources: web browser 1 and web browser 2 to which I assigned a different url.
I configured the audio settings like picture attached
These 2 urls broadcast audio.
The 2 audios broadcast in the OBS Studio mixer
When i record,i can see video but hear only audio from web browser 1.
Why?

thanks