Hi Fmz38,
Thanks for reaching out in Apple Support Communities. I understand that you're seeing some flickering when watching videos on the Netflix website using Safari on your Mac. I can see why you'd reach out about this behavior; I'd like to help. First, I'd recommend working through the steps in the following guide starting with "Check Safari extensions:" If Safari doesn't load a page or webpage items are missing
If the behavior continues, use these steps to start your Mac in safe mode and test again: Use safe mode to isolate issues with your Mac
If the issue seems to be resolved, restart your Mac normally and test again.
Should the issue persist in safe mode or after you restart your Mac, use these steps to test in a new user: How to test an issue in another user account on your Mac
Do you notice if this affects other websites you stream video from?
Let me know what you find.
Best Regards.