bug#42804: mkdir saying it can't create folder although it created it

[Nick Levinson]

When I use mkdir, when it succeeds sometimes it has no message, which is 
acceptable, but sometimes it says this:

mkdir: cannot create directory '<folder-name>': File exists
But the directory didn't exist before I used mkdir to make it, and I show 
hidden files, thus also hidden directories.
I suggest the message be clarified or corrected.
Thank you.
-- Nick