Think OP is referring to the last-minute amendments.
There have been cases where the committee meeting/etc was scheduled last minute, but that's super-rare (and not allowed in a lot of legislatures, actually).
Here, i believe it was scheduled a week ahead of time, from the data i can find.
Just because the people who are required to vote on something know about it doesn't mean they are not secret or "secretive." This is the public's business.
> nor is it questionable why they are legal: Everyone who is supposed to vote on those amendments did. In favor.
There are frequently other considerations in whether something is legal than whether the people who needed to vote on it voted for it.