Something strange is happening with Publisher CE4.
After uploading the images and checking if the download image link works the reference file name has a "-" added to the suffix.
I checked it adds a "-" to all the images as well.
I checked the Lightroom Preferences and there is mention a Dash (-) is used to replace illegal fine name characters.
I'm not sure if this is doing it?
So no space as the end of your filenames in Lightroom? How about other characters?
Do you have any renaming going on during publishing? Perhaps something that's adding that dash?
Check in Publisher setup under File Naming
I think more than likely you have an errant space in your file rename settings for export/publish in Lightroom. Maybe you tapped the spacebar by mistake or something; anyway, that's the first place I'd look. Or if you're batch renaming files in Library, check your naming preset to ensure there's not an errant space there.