Unfortunately this didn’t solve the problem, and purging the cache didn’t help either. So I turned off CF on this one.
I’m going to involve the test environment, there are no visitors there, and there is less nuisance. Good to try something there and try to reproduce this. But I still believe that this is not because of my server, because it arose spontaneously.
There are four other people in this thread who have reported this problem. So I assume there will be further research within CF? This clearly seems like a serious problem.
I really hope the forum-support has any ideas. Later today I will dedicate another email.
Maybe the senior staff has some ideas.