The hardware support for Blu-ray burners in Max OS has been completely functional and stable for over three years now, since Leopard. It is the authoring software that is lacking.
I have an external BDR-203 (the predecessor of the BDR-205) installed in a 3-interface external enclosure, including eSata connected to to my Mac Pro via the OWC backplane adapter to the motherboard. I just fired it up and it works fine with the Apple Finder and our BluStreak burning software using the eSata connection. It also works fine with Firewire and USB.
Software that uses disc burning on the Mac must take exclusive access to the drive in order to operate it. (It is the same on WIndows). If one app has access, no other app can see it. If Encore were to lose track of what it was doing, what you see might be the result.
I can’t speak to Encore burning, since we don’t use it because we must decide the disc directory layout for layer break and seamless playback purposes. But as an example, when we take control of the burner, any mounted disc disappears from the Finder, and when we exit our program, the disc is automatically re-mounted.
If you like you can download our free burner software here:
https://blustreak.dvdafteredit.com/blustreak-burner
Regards,
Larry Applegate
https://blustreak.dvdafteredit.com/