Illustrator issues with opening multiple files - Mac OS Big Sur

[#1]

I have the latest versions of Big Sur (11.0.1) and Illustrator 25.0 installed. Everytime I want to open more than one file I end up with graphic issues. It's not possible to perform any editing actions on affected tab. 

When I switch off the GPU (Radeon Pro 555X 4  GB) in Ai Preferences everything works fine.

[#2]

Hi Martin,

Apologies for the delayed response. I hope this issues is now resolved for you.

If not, please make sure you have updated the OS & Adobe Illustrator to the latest version.

You may follow the help article(https://helpx.adobe.com/in/creative-cloud/help/creative-cloud-updates.html) to update your app. Let us know if it helps.

Regards,

Ashutosh