Does Plex support 4K 4:2:2

I have just received a number of 4K videos which use 4:2:2 chroma subsampling.
When playing these videos via a NVidia Shield TV I get sound but no picture.
I have one of the latest Samsung 4K UHD TV's and I'm using a high performance PC as the Plex Media server.
Other 4K videos with 4:2:0 chroma subsampling work perfectly.
The NVidia Shield TV is set for 4:2:2 BT.2020.
Is this a limitation the Plex app on the NVidia Shield TV?