Rather than being browser related, it may be HCDP related. That’s a type of DRM/encryption. Some drivers may block screenshots when that is active.
If Netflix detects it can’t use HCDP, it runs all video at a lower resolution (720p or lower, I believe). Why it can’t use it could be your monitor, your cables, your browser, your drivers, etc.
I noticed that Netflix uses HCDP because my current monitor setup claims to support it but doesn’t. So I get static whenever I load the Netflix app or site. It seems to be due to the particular HDMI-to-VGA adapter that I use, as the adapter in my dad’s computer works just fine.
It’s not a big deal to me as I almost never watch Netflix, and I can still watch it on my phone.