Samsung Q60R Qled

Hello all I just upgraded and setup the tv to my Onkyo receiver through the ARC input 4 to the back of the TV to the AV. Simple right. All of the TV apps I use to stream Netflix, Amazon, YouTube TV, with these connections are passing Dolby Digital audio which is what I wanted. But the only TV app that isn't putting out DD audio is YouTube it is out putting PCM. I checked the audio settings on the TV itself and Dolby Digital + is greyed out for selection. Question is how can all the apps play in Dolby but with the exact same connections in place YouTube is putting out PCM audio?? I could use some help thanks

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