I've redacted the name of the user in question, but as far as I have seen they've been an upstanding and productive member of the community, which made me mildly surprised to see that they have a flag weight of 75 (the default is 100). I decided to investigate how that came to be, and looking at their flagging history (as moderators are able to do, in addition to the user themself), I see nothing:
Even flags on posts that were deleted should appear on this page, so I don't understand how this is possible. I looked at a few other randomly selected, moderately active users, and none of them have an incorrectly low flag weight, so it would seem that this is localized to this one user. Of course, I will provide the name of the user to the SE team (so they can take a look at the page themselves), and I'd be happy to do so in public if the consensus is that this is not a big deal; I just thought it'd be better to err on the side of privacy first.
By the way, while doing this I noticed that the flag weight audit page always reads "Your flagging history", even when it is not the user themself viewing the page. Obviously a very minor point, since the only people who can look at a user's flag weight audit other than the user themself are the moderators, but I decided to raise it on meta.SO.