Less than 10 rep for an upvote without hitting the reputation cap?

Question

Apologies in advance if this is a duplicate, but I couldn't find it.

The reputation summary on SO tells me I received 180 reputation today (if I click the envelope icon, then "summary", then "today"). As I understand it this is 20 less than the cap of 200. An answer that I posted earlier (within the last two hours), before I reached 180, has 1 upvote and 0 downvotes and earned 7 reputation. My most recent answer has 7 upvotes and 0 downvotes and has earned 5 reputation. No CW stuff is involved, as far as I can tell.

Can anyone explain to me what's happening here?

Edit, in response to Marc, but also as an afterthought: no, I haven't done a lot of downvoting nor been downvoted. Specifically, I haven't reached the cap and then gone down to 180 or anything like that, nor do I have enough downvoting to make the difference. Nor did I reach the cap at all, to my knowledge.

Edit 2: Marc's point about unaccepted answers seems valid, except for that it happened that two questions got weird (<10) amounts of reputation. Still possible?

Edit 3: it happened again today. I was at 182 reputation for the day, including -3 in downvotes, and I just received 7 points for an upvote, capping me at 189. So frustrating. I'm almost certain I didn't reach 200 at any point today.

Edit 3.5: Right after I typed that, I had two answers accepted, putting me at 219. I thought about the case where one of those got in while I was still at 182, but that would put me up to 197 and then I would have received 3 for the last upvote, not 7.

Answer 1

Interesting... this pattern is repeated on Jon's rep tracker. Have you perhaps done lots of downvoting today? The other possibility is that you've had some answers unaccepted - i.e. you hit the cap briefly, and then have had points subtracted due to losing a green tick on an old answer.

Oh, there is another possibility - it sometimes happens that a well-meaning overly grateful user upvotes your account heavily, triggering suspicious voting patterns. This then cancels the suspicious votes; it is possible that 2 of these votes were part of your days rep.

i.e. say you had +180, and then somebody upvoted you like a crazy mad thing; you'd max at +200, the rest would be discarded, and then (at some point) their 30 (or whatever) votes are cancelled taking you back to +180. Don't ask me the exact details of the suspicious voting algorithm, as I genuinely don't know.