I did not mute anything and I did not change anything in preferences either.
I was reading the posts and I didn’t pay attention to the additional information [qubes-users] making it clear that this is a post from the mailing list.
This morning there were 3 posts displayed by user Guerlan from the mailing list and these posts were still displayed after I had logged in to the forum.
Maybe I pushed the “go back one page” in Firefox because of the blue dot that appeared while I was writing my answer but I am not 100% sure. This might be a logical explanation. At least I did that (or refresh) in the past when new answers were posted during writing a comment.
I guess I would have noticed that I wouldn’t have been able to answer anyway (because of the muted category).
Sorry, that I didn’t exactly remember. I was a little confused until I understood the connection to the mailing list.