Safari is continuously flickering after the macOS 15 update

Restart in Safe Mode.

This will perform a Disk Repair, clear cache files and only load Apple Software, extensions and fonts.

The boot up will be slow and can take some time - Normal.

Safe Mode will also eliminate Third Party Software, extensions and drivers from loading.

It will only load the Minimum amount of Core Apple Processes to allow the the computer to function at a reduced Level of Performance 

Does the issue present in this mode ?

I'm also having this issue. Safe mode did not eliminate the problem.

Hii

After a long session with the support team yesterday and today this solved it:

Disabling extensions in Safari, then turning them on again one by one. With that, the problem disappeared.

In the end, I could even enable all of them again, according to the senior support staff, just turning them off and one again seems to have been enough in this case.

Before that, we created a test user, which did not have the same Safari flickering, indicating that the cause was something I installed.

Hope this helps