It looks like some of Deltix Round Spring 2021 got rejudged to include uphacks, including causing my D to go from passing to failing, and also affecting the placing and rating.
You can see in the announcement that I originally got 5th, but the scoreboard now shows 10th, and my submission 117918101 shows an extra 10 tests beyond the 127 that other submissions have, like 117881477.
It seems like this bug is several months old: galen_colin posted about it at https://codeforces.com/blog/entry/88000, and MikeMirzayanov didn't fix that contest and said he'd "try to avoid it in the future". This bug is totally unacceptable, it significantly affected results a full 2 days after the contest ended; imagine if it affected prize distribution. I have no idea when these hacks were added, but it's definitely not akin to in-contest hacking. MikeMirzayanov needs to either fix this properly, or disable uphacks until after standings are finalized. It's already happened twice, and it definitely cannot happen a third time.