Lightroom - external edits missing filenames on export

[ancient_mariner]

Curious thing that's been going on if I edit a photo in Nik Silver Efex, it's exported as a tiff, then re-imported. After the re-import LR will not use the original file name and number when exporting the file for upload or printing, even if I edit the file name in LR to not include the - that Nik gives it.

Any idea why this happens, and what I can change to stop it?

 

[BrynBoru]

I tried to understand this, by experimenting. Eventually I exported an image and then changed the name in the export location. Then I dragged it back into the original folder, but as a jpeg.
I've no idea and would like to understand the mechanism by which Nik SE gives its conversion its file name. Even though I tested this on the Nikon camera file name DSC_etc, it latched on to my custom naming system plus 1!
Is it something to do with the initial setting, which I choose as "Edit a Copy with LR Adjustment"? That way it will not do anything to affect the original file, which presumably includes file naming.
Baffling!