This first happened to me within the last week or so on an iPhone 6s. CF was unusable on Safari, and after some luck on Chrome and Firefox, unusable on them as well. I started using the new browser, Brave, and have not yet experienced the same problem. IIRC and FWIW, Brave was started by that high up executive-developer at Firefox who was forced out of his position a year or two ago or whatever, so he probably has a pretty good idea what he is doing. I am posting this using Brave and FWIW I see ads.
Also, I was aware of this thread when I got my phone and was very careful. I only ran CF on an Adblock browser at first. I have never experienced the problem on it, but CF icons etc. are sometimes jumbled up, not where they are supposed to be, and sometimes blocking the text.