Create a file in a location.
Copy file to another location.
Edit file, increasing the size.
Copy file back to original location.
Get a warning dialogue that file will be overwritten.

Problem - how do  you know which is the newer file? There are no details, which
are absolutely necessary in order to replace files.

This is especially important if you work on a computer, but have a USBstick that
you copy stuff to - did you work on the computer or on the stick? If you know
which file was updated more recently, you can find out. Otherwise, if you're
slighly confused, you might overwrite your newer version with the older version.
Since this can (and probably has) resolve in dataloss, I'm keeping the severity
Normal, but I believe it should be higher.