I’ve gone ahead and moved this to it’s own thread as it seems like a different issue compared to the “Browser blocking media image requests” thread where the clues pointed to a fundamental browser compatibility issue that needed to be worked around. 
It’s hard to tell based on the information provided so far, but since it’s an intermittent issue it could be something with Blue Iris itself and that’s probably the first place I would recommend troubleshooting.
A common approach to workaround issues with Blue Iris streams hanging is to use a refresh interval on the Media. You’ll have to play with it to get a feel for what works best for you - could start at 30 minutes and then go up or down from there. The other approach I’ve seen taken with Blue Iris is to use the image snapshot URL and have it refresh every few seconds – for example, refresh every 5 seconds, then have the Hyperlink action on the media tile open the live stream.