If you change your software to comply with "middleboxes" that don't follow standards, then you're admitting your own software is faulty, not theirs. In this case, though, the TLS v1.3 standard actually carved out a portion of the standard itself just to comply with shitty middleware. You know what that says to me? Standards are pointless. Just make a middlebox, make it do whatever the hell you want, and everyone else will bend over to support you.

This is yet one more reason why we need software building codes and regulations. If software people are unwilling to protect their own standards, the government should. It might fix the 20-year mistake of allowing "the web" to become a defacto network transport layer and application platform.