Solved

"You need a WebGL browser, try installing Firefox"

Firefox worked flawlessly as expected

I'm still puzzled about the different results Chrome users experience

Also, this make me think of a suggestion:
-Could it be possible to have some sort of permanent "dummy" race to check the raceviewer (and it's settings) I think it could be useful you know, so you don't have to tweak the setting while in race and also when you need to test the connection/server/race viewer ; it could also help to reduce the threads complaining about a race not happening or failing to connect because if this "dummy" race was unreachable it would imply there is a server side issue (maybe a pop up or a more detailed message could be available? )
Just my 2 cents

When it next crashes can you try to load the developer tools in chutney and go to console and let us know any errors which may get down there. As with continual races there is usually always at least one race running on the home page there is a spectate button which shows you a list of other races you can watch and try and get the viewer going.

How many tabs have you got open while doing this too.

Have you tried changing your setting via the Web to change your viewer to basic mode does that make any difference?

I also experienced lag, freeze and "WebGL failed to load" while Race viewer loading, but It only happens on my chrome if any VPN extension like Zenmate or program such as bluestacks running in the background

Hold the phone you said you will use firefox on your laptop & not your desktop. It is running perfect, does chrome work on the laptop too?

Using a different device and it working fine indicates that there is a problem with your desktops configuration.

That's news to me. I didn't know IGP worked on a Mac.

When it next crashes can you try to load the developer tools in chutney

As with continual races there is usually always at least one race running on the home page there is a spectate button which shows you a list of other races you can watch and try and get the viewer going.