I'm wondering the same thing. In a couple of proposed lumps on the IOC website, NACC 2023 proposals are referenced (see below, on the Mealy Amazon and the cacique). Which means there is at least one batch of proposals out there. Which makes it even more intriguing why it's not posted.
SACC proposals have also referenced NACC proposals in the last few months
I've commented on this elsewhere. The least conspiratorial answer could simply be that the NACC relies upon a volunteer from the AOS to update this section of the website, and that person either left or is overwhelmed at work. Hell, someone could have just lost a password. Laugh but I have heard of that happening enough times with other equivalent groups that it wouldn't shock me. Alternatively, due to the WGAC reconciliation process, the NACC is overwhelmed with more proposals than in a normal year. so voting and debating these has taken precedence over getting them posted, or its enough of a constant stream that folks in charge are waiting to get them all at once rather than have to deal with posting proposal batch "L" or something.
Alternatively, it could also be a change in the set-up of how the committee operates. There is apparently discussion of a separate NACC committee taking over common names. Perhaps, due to increased internet criticism, some of which is pretty scathing, they are less inclined to be more transparent. This way they feel they don't have to worry about outside pressures or jumping through extra hoops (like letting ebird reviewers vote for a meadowlark common name) Or it could be increased discord between the committee and other taxonomic/taxonomic-related groups, like ebird or WGAC. I will just say the longer the proposals don't get posted, the more likely it feels that it may be an intentional move towards less transparency.