Often times (not always) a running or loaded file can only be renamed at the second attempt. First attempt to rename in Dolphin fails (it just doesn’t do it after confirmation).
Did you notice that behaviour? It’s kinda annoying…
Yes, the same thing happens to me, it’s not systematic but it happens very often.
Never had that yet. But I do not rename too many files too often 
Found on the KDE bugtracker: https://bugs.kde.org/show_bug.cgi?id=519175
Now we just have to wait.
Damn, this bugtracker website is BUGGY as hell 
It didn’t take my username as login (“@ char missing”), so logged in with email.
Now my answer shows my email adress instead of a username, with no option to change that.
Editing the answer was like “Somebody else tries to edit your message. Do you want to submit it anyways?”….um, yes
Now there are two answers of mine…
Bravo KDE, this is pure IRONY 