I don't know if "most conditions" is even true. Even when it's only running a handful of processes and I have plenty of ram free I cannot convince it to use more than one process for twitch tabs.
The bug might be fixed right now but yes I definitely wanted it, because opening a twitch tab was consistently causing the video in the old tab to hang for a couple seconds.
> There's a flag related to isolation in your chrome://flags that will do per-origin.
What flag is that?
I even tried setting --process-per-site-instance and it had no effect.
I think there are some restrictions on tab "navigation source". (Something about a fairly obscure JavaScript feature that links tabs opened via click navigation, if I recall correctly.)
Does this also happen when you type the Twitch URL in a new tab?
Yes. Or even if I have another tab on youtube or whatever and type in twitch, it will close the youtube process and switch to sharing the existing twitch process.
Do you actually want it to? Or are you just experimenting? FWIW There's a flag related to isolation in your chrome://flags that will do per-origin.