In this case, it doesn't sound like they're reverting it because of overall breakage, but rather because it breaks the tool that would otherwise be used to control TLS 1.3 trials and other configuration. Firefox had a similar issue, where they temporarily used more conservative settings for their updater than for the browser itself, to ensure that people could always obtain updates that might improve the situation.
Even protocol state (equivalents of TCP FIN/SYN/etc) is encrypted, to ensure that middleboxes don't get ideas about what the protocol is 'supposed' to do - ideas which make it hard to change the protocol in the future.