Sorry for the double post - and please no one roast me for this.
There's a lawyer on Tik Tok who mentioned payment issues within the last few days (JQK Immigration). They said they were having credit card filings being placed on hold due to payment issues, and then these issues were later found to be clerical issues. They ended up getting the NOAs a few weeks later.
They said 1 in 20 of their filed cases saw this, and that it started cropping up in December.
Just wanted to share - maybe its a simiilar issue to what you are seeing, especially since it says balance due is $0.