Streamlabs OBS latency issue

I’ve been doing test streams on youtube using Streamlabs OBS. The issue im having is that whenever i add a source to a scene such as a picture/video/audio or any source, it runs smooth on my end but on the viewer end, there’s a very long delay (15-30 secs) before they see the new source. Hoping someone can help me with this. I’ve had this issue on my IMAC which is pretty powerful. So i’m certain it’s not a CPU issue. i’ve tried many different settings in streamlabs & nothing has worked.