It breaks video playing in facebook. --- 'fbcdn.net/*.mp4' files are blocked by CORS security.

I had a look at the exceptions rules and it already has '*.facebook.com > *.fbcdn.net'. The exception rules are not working anymore? Have to disable to be able to watch videos.

Only way to find out this was the cause of the error was to enable/disable obvious culprits like ublock, decentral eyes, etc.. one by one, and this addon was not at the top of the list.