Lightroom Classic: Publishing Smart Collection of videos to hard drive does not complete properly

I'm trying to publish a smart folder of short iPhone (6S/X) videos using the Hard Drive publishing service in LR Classic 7.5.
The videos are successfully created in a "tmp" subfolder in the target location, but when the export of each video has been completed, it is not moved out of the tmp folder and into the main target folder.
Also, they are not marked as "published" in the Lightroom interface, and the files remain in the "New" section of the publishing screen.