No Dolby Digital 5.1 from X1 Box for X1 Apps

My old Comcast box had a TOS output that I had connected to my Receiver in order to get 5.1 Dolby Digital.
My new X1 box "Comcast X1 XG1v4-A 4K Primary TV Box" Does not have a TOS output, only HDMI out.  I 

connect the HDMI out to my TV's HDMI input. My new TV does not "pass" Dolby Digital out of it's TOS 

output.
So I do not get 5.1 to my Receiver... my Receiver is not ARC, so I cannot use HDMI Audio to it. So I 

purchased an HDMI Audio Extractor, and connected it between my X1 Box and my TV.  [X1 Box: HDMI Out] 

>>> "In"  HDMI Audio Extractor  "Out" >>> [to HDMI on TV], AND Extractor has a TOS output that I connect to 

my Receiver. 
Now here is the strange part: Watching a TV channel from the X1 Box, my Receiver shows "Dolby Digital" 

and I get 5.1 audio from my Receiver.
BUT, If I run ANY application built into the X1 Box... Netflix, Prime, Disney Hulu, Vudu, I do not get ANY 

audio to the Receiver. 
It cannot be my extractor, since it works fine on a TV channel.  
Going in the Audio settings on my X1 Box: I only have 2 choices for "HDMI Audio Output" 
1 = "Auto Detect Dolby Digital" - Which if I select - I get NO Audio for a TV channel or an X1 App.
2 = "Expert Setting Dolby Digital" - Which does give me Audio (5.1 DD), But only for a TV Channel... Nothing 

from the same X1 Box if I choose an App from the box! 
Calling Comcast is no help, they just have you power cycle the X1 Box, or they send the X1 Box a reset, 

which has NO effect.  And the Comcast Call Center people have no technical knowledge beyond that.
If only Comcast had a 4K Box with a TOS output, but they do not.
HELP PLEASE!!!