Literally everything. It starts off fine and slowly has audio drift. The only way to fix it while watching is to exit what I'm casting (phone, tablet, web browser) and restart.
I've tried a reset of everything (modem, router, Shield) and it still, eventually happens.
FWIW, the modem is a Motorola ARRIS 6141, and the router is an ASUS AC-87R on the 5Ghz channel. Firmware is up to date on everything.
Anyone run into the same issue and have a fix?
Is the shield connected to an AVR?
Try going to settings>display&sound>advanced settings>audio video sync see if that works.
You could try the Google Cast Receiver beta. See if it improves this issue. https://play.google.com/apps/testing/com.google.android.apps.mediashell
Been dealing with the same issue... I have a 65 LG OLED TV.. not sure if the TV has anything to do with it but after I disabled Dolby Atmos through one of the TV menus everything synced up properly.
Mine does but i use a soundbar and power cycling it always corrects it.