I had the same problem, just disabled hardware acceleration, and the glitch is gone after restarting Opera.

@cvuzda said in There appear (graphic/video) glitches/artifacts in opera browser:

I see like problem on Ubuntu 20.04.1, linux 5.8.6 and opera 71.0.3770.271.

https://imgur.com/a/9Oqu8p2
https://imgur.com/a/OObChqZ
info about system:
https://imgur.com/a/prM5FNF

parity solve problem - enable vulkan in opera://flags

Yes, it did solve my problem.

If I disable hardware acceleration then the right mouse button doesn't work anymore. So I just have to live with the glitch until there is a solution.

I had the same problem, just disabled hardware acceleration, and the glitch is gone after restarting Opera.

I voted no.
Well if this is the direction that opera is going, then I will say it goodbye. I have used opera since it came out for the first time and used it ever since.I just liked it for it possibilities like to hold the right mouse knob and click the left one to go back one page. I also used it for placing the tab bar at the bottom. Those things doesn't work anymore. I hope opera 15 or 16 will never come to Linux. I tried it in windows but I don't like it!!! If I wanted Chromium I will use Chromium and not Chromium with just the name of Opera above it. It's not what most users of Opera want. Yes there were some issues that didn't work in opera, well then I always can use another browser. It is to bad that just those things that made a browser useful will disappear.
Too bad that the opera team has decide to go to this direction. I will probably say opera farewell. I am very disappointed in the new Opera.