YouTube playlist stops playing in background when one sec extension is enabled in Zen Browser

Hello one sec team,

I'm experiencing a problem with the one sec browser extension in Zen Browser.

What happens:

• I open YouTube and complete the one sec breathing intervention.

• I start listening to a YouTube playlist.

• When YouTube is in the background and the current video finishes, the playlist stops instead of automatically playing the next video.

• I have to return to YouTube and complete the breathing intervention again.

What I've tested:

• With one sec enabled, background playlist playback stops.

• With one sec disabled, background playlist playback works normally.

• When YouTube stays in the foreground, playlists advance normally.

My settings:

• Browser: Zen Browser (Firefox-based)

• Intervention: Enabled

• Timing: Immediately

• Duration: 6 seconds

• Re-intervention and subdomain configuration: Pro-only.

What I'd like:

I want to keep the initial breathing intervention when opening YouTube, but allow automatic playlist transitions to work normally in the background.

Could you investigate whether this is a browser extension bug and whether there is a workaround in the free version?

Thank you!