For some time now I notice garbled/fuzzy/scrambled/... visualisations of different elements: # '''pdf thumbnails''': see first attachments. This happened both in the older as well as in the newest pdf viewer built into Firefox. I must say it happens most of the time, but not always. # '''preview of uploaded pictures''': sometimes when you have to upload a picture, after a successful upload to a site, it shows you a rendering of the uploaded picture, a preview. This then shows a similar "scrambling" as the pdf thumbnails above. Unfortunately I don't have a screenshot of this. # '''repl.it console''': the second attachment shows you how the first line of the repl.it console is scrambled/garbled. This happens for every repl and whether for new or existing ones. All above issues only happen on Firefox and not on Safari, Chrome or Brave. Very strange, and I cannot find any related issue online. The above three items are the only occurrences. All other items are rendered correctly.