When I played around renaming a file to trigger ( https://bugzilla.xfce.org/show_bug.cgi?id=12264 ) it happened several times that Thunar renamed the file and created a virtual clone in the list view.
It had the same name and editing one of the files changed both.
Renaming it again lets the clone disappear.
Actually it does not really exists as a file: Another instance of Thunar won't display it and it cannot be found by the terminal.
Created attachment 6525
Screenshot of the issue
Sorry for the late reply !
I cannot reproduce this bug. Neither with thunar 1.6.11, nor with master.
... possibly as well this bug got fixed by the fix for bug 12264.
Could you please take a try with thunar 1.6.11 and check if it is still an issue for you ?
Since there is no further information, and probably the cause already got fixed I will close this bug for now.
Please feel free to reopen if it is still an issue for you !