Hello MWilson
I have Studio 19U since one week with the latest patch installed and I'm faced with the same problem.
My footage comes from Sony HDR-TD30 and is recogniced as 3D. I can export 3D Anaglyph as well as
3D side-by-side, but Exporting a multistream 3D ends up with a Blu-ray disk, that replays only 2D.
I have this problem since Feb. 2014 with all versions of Studio 17U and this bug seems to be unsolved
up to now. My last successful exported multistream Blu-ray was from Jan. 2014.
This is an open issue with Corel support.