trollhunter B/R does not copy

[idic5]

trollhunter blu ray does not copy. it establishes the folder-file structure on the left side after the initial click of the disc control, and it starts the process of copying when the makemkv control is clicked, but about mid way or so, it hangs. two b/r devices this occurred . any insights? there has been one person in the past ( '12) with no answers. how to proceed or diagnose? no other discs does this occur. makemkv works for all other disks

[Woodstock]

Do you have debug logging turned on? Are there any error messages when it "hangs"?