The best conclusion I could think of is that my problem was a consequence of caching (as you stated) further complicated by some time delay (the time it took to remove Cloudflare). I also observed that I likely misunderstood your instructions. Specifically, the sequence 2, 3 and 4 in the article https://github.com/adriatic/screenshots/issues/34 have the same effect as step 2 alone.
In other words, step 2 is sufficient to disable the title on the page “Help” – steps 3 and 4 do not do have any effect on the title of the “Help” page.
At this point, I am happy with this solution and am leaving up to you whether you want to continue this discussion (to make sure that there is no bug in your code).
Thanks for all your help