Indeed, I tried a fresh install of Dopus on clean Windows 7 on virtual machine, and it has similar behavior. For the sake of consistency I did a proper testing of other audio formats supported by Audio Tags plugin except .m4p because I don't have any and iTunes Store nowadays seems to sell only DRM free music. I found that the same issue happens with .opus .m4a .aac and .fla files, in other word Directory Opus reads tag data from them without a problem but it is unable to display it in Metadata Pane.
I would be grateful if you would fix it, especially m4a files, because they are pretty common among the people who use apple devices. Also I encountered another thing that might be a bug. A green rectangle is displayed instead of .wav thumbnail, Explorer seems to handle .wav thumbnails fine(with the help of Icaros).
Dopus
Explorer
I have uploaded 7zip archive with this .wav file.
Link
Password:
5698
I'd appreciate if you could look into this issue as well.
Thanks for the information. 
This remaster will be a nice addition to my collection of different versions of Death Magnetic(I already have this particular CD, remastered version that I bought at the iTunes Store(they cleaned it a lot and added some bass), and another remastered version of unknown origin). 
But, strange as it may sound, the more I listen to the remastered versions of this album the more I like the original release. Yea it has dirty sound, but it gives more of the "impact" with all its raspy and overloaded riffs IMHO. 