File renaming with ~photo overrides original file number in metadata

When I transfer images and videos from my iPhone 8 plus to my new iXpand 256GB, it changes the filename of every single file to have ~photo or ~video after the file number. When I go into Lightroom to modify the filename, if I select Custom Name + Original File Number, the the file number comes out blank. iXpand appears to have stripped the file number from the metadata of the image. Help!