Under what circumstances will windows generate two folders of the same name in the same file tree po

[Destination]

In essence I am backing some items up today.
Using a drive I haven't used in a while for an offsite backup.

Copying across a few directories, and instead of overwriting or asking to replace or copy what is therwe windows seems to have decided to make an entirely new directory with the same name as the old.

In this case on the L: drive, two 'pictures' folders

Why would this occur?

 

[Destination]

Ah superb, it had me very concerned, but it is the secondary backup rather than the primary anyway.
It was copy file operations, just find it strange that 99/100 windows will bring up a prompt box stating folder of name already in destination do you want to copy/replace etc, this time it did not just started copying.

I assume in some way this was related to the copy of a main windows directory (pictures, videos,document)

Thanks for the info, and reassurance.
Going to do a full drive test after backup complete anyway.