Audio Extractor

I am trying to monitor the audio on the HDMI out on a ATEM Mini Pro using an audio extractor. I have multiple sites that use this setup and sometimes it works, most times it doesn't. The one thing I have noticed is that the red light for the Toslink optical port is steady for ones that work and flickers for ones that don't. The light will be solid with any other input source except the ATEM. I have tried multiple configurations with different brands of extractors and known good power supplies. Do you think problem this is caused by the HDMI signal or something with BMD's ATEM control software version? I'm at my wit's end trying to figure it out.