is the shield plugged directly into the RECEIVER? or is it plugged into the tv?
is your hdmi compatible with 4k/hdmi 2.0/hdcp 2.2?
what are your exact shield device, and plex quality settings? you want to have hdmi pass-though enabled.
kodi and plex are not the same, you cannot compare them.
post a screenshot of your server dashboard with the problem playing. you can copy/paste the image directly into a reply. actually without plex pass the dashboard won’t tell you much.
you could also try installing tautulli for better details into the streaming
if you have not already read @ Plex, 4k, transcoding, and you it might be useful, however the shield itself should play truehd fine assuming everything is configured correctly and compatible.
play the problem movie, then download logs and drag them into a reply.
Plex Web > settings > troubleshooting > download logs
