RAF files in LR folder. Select Library - convert photo(s) to dng. Do not check delete raw. File converted to .dng. Original file disappears from folder. Can see file when select synchronize folder. Choose file, add (only choice). File now added to folder but with file name .dng even though metadata confirms it is a raw file. I don't think the original should disappear from the folder, and if I have to sync to get it back, it should have the correct file type listed.