Lightroom Stealing Original Files During Import

Recently I had my PC split into two drives. C Drive is SSD and runs all of my programs. D drive is a moving HD and has all of my photos stored. 

LR Classic runs on the C drive. Suddenly whenever I import a photo from the D drive, LR takes the file OUT of the D drive. As in, I go back to the original folder in the D drive, and the file is gone. Then when I try to add the photo to my folder of stuff to sync, so I can edit on my ipad, LR doesn't seem to actually have the file. It won't sync. I have to export to the C drive, then re-import from the C drive. 

Any thoughts? Seems LR shouldn't have a problem working between drives like this.