Fóram Tacaíochta Firefox

Today, when I opened Firefox web browser and go to a site(s), I get a different appearance to what I am used to and I don't like it. I have downloaded the latest version of Firefox (91.0) but this has not helped. I use Firefox on a Mac. Any suggestions on how to revert to the previous appearance would be appreciated.

Firefox seems to be partially transparent, which makes my background to bleed over the Firefox windows. I have already reinstalled it, cleared cookies and data, refreshed firefox, made a new profile and even deleted all firefox files and cache in ~/.mozilla/firefox and /usr/lib/firefox/ & firefox-addons/.

And despite all of this it still does not seem to fix the transparency issue, apart form it all the browser works great only that visual bug annoys the experience. The errors seems to disappear if Firefox is launched in Troubleshoot Mode but launching without it brings back the issue.

NOTE: It can be fixed by installing a fresh copy of the system which is not convenient. Error happens in Firefox-92.0 in linux.

Some solid colours on certain webpages do not appear whilst on Firefox. The background will show up instead of the colour the image should be. I have tried to delete the cookies and cache on Firefox as well as trying Firefox in troubleshoot mode to no avail. Whilst writing this question, I have also discovered that taking a screenshot of the issue shows how the image should look as opposed to what the screen shows. Attached are some images of the issues I am facing, two images are of what appears on the screen and one image is the screenshot from the webpage which is what should have been shown. Apologies for some of the photos, I had to take a photo of the screen with my phone to show the issue. I have also closed the browser multiple times and restarted my computer, any help would be appreciated. Thanks in advance.