WD Live, Netflix and Dolby Digital

[Born2bwire]

I just got a WD Live Streaming Media Player (God, I wish they would differentiate between the generations of the player more explicitly) and my intention was to use it mostly for Netflix for the HD and Dolby Digital streams. I don't have a Dolby Digital Plus receiver or one that can take in an HDMI feed so I got the WD Live since it has the optical out. What confuses me though is that almost all of the Netflix streams that claim Dolby Digital do not send DD to my receiver, only PCM stereo. However, I have found two shows, Sherlock and Parks and Recreation, that do send the Dolby Digital consistently.

Has anyone experienced troubles like this? I don't think it's a bandwidth issue as I can get the X-High HD streams.