ATEM Extreme - FTB causes live stream to end?

I've noticed something recently. After I set my main audio fader to fade with the fade to black function, I now find that the live stream will end sometime between 20 and 60 seconds after enabling the fade. The red "On Air" button will start to blink when the stream ends.

It's not clear to me if this is the ATEM doing this or if perhaps my streaming server is sensing black video and no audio and is ending the stream.

Anyone familiar with this?

Some streaming services including I think Vimeo will and the stream on no data. What they consider no data can just be the very low bitrate of black which has a bitrate of almost zero as very little data is required for every pixel being 0 and having no change. I am not sure if there are options for disabling stopping the stream if it "loses" data but you might just have to change provider, not fade to black and fade to something else.