This sounds just like the issue i had with many tve stations giving a 403 no permissions error error during commercials. it would lock up or just buffer and the bar came up.
but it was resolved in sever update shortly after not to long ago.
i have been playing Fox News for 20 minutes now and, only sometimes when there is commercials, is there a slight buffer happen when i changes/loads new commercial. that happens on many TVE stations though.
i have a 2019 Shield Pro (using Hardware decoder) and the 2019 Tube TV model (set to Hybrid decoder) Quality is set to original.