Did you ever find a solution to your problem? I have a similar issue, where chunks of a CMAF stream aren't retrieved and I get a DecodeError (6) and NETWORK_LOADING state if I inspect Media and MSE debug traces, but I can't figure out why. This was working fine until recently.

Has anyone here found a fix for this? This is still broken for us with Shaka and Safari 15 (desktop and iOS), and appears to still be broken in the 15.1 beta.