This has its own question on meta.se. But four does equal five!
The upvote you received at 09:16 is still 'unread' (marked in yellow) at the top of the list. If you refresh the page, it should show 3 events. I was able to reproduce it in my reputation tab:
This one shows 'unread' reputation changes in yellow, the 22:34 upvote on 'Convincing superstitious people' is also shown in the event log for the entire question, but isn't counted as event nr. 5.
Here, I refreshed the page. You can now see I have 5 events for that question, including the 22:34 upvote:
Apparently, things have been like this since 2012...