The executive board of the Democratic party met and voted on a set of rules that allowed Roberta Lange to take complete control of the convention, without a vote. There was a petition filed by change.org to change those rules, and filed a lawsuit in court which was dismissed. The rule change was supposed to be voted on at the beginning of the convention, but Lange didn’t allow that discussion and vote, passing the rule changes unilaterally, and that’s when the shouting began. That doesn’t sound like the bipartisan agreement on rules you’re describing.

Of all the accounts on both sides, you are the only one who claims the Bernie delegates were “mythical” no-shows. If that was the case the Sanders delegates being disqualified wouldn’t even be an issue, so your claim makes no sense.