I noticed an increase in my reputation today further to an upvote to one of my answers. Surprisingly, the increase is 6 units, not 10. I'm aware of the ways one can gain/lose reputation (also saw this closely related question), and based on my recent actions I guess I got 2 down votes to some of my questions/answers. I don't mind the "loss" of these 4 units, but I would like to see where/how I lost them to potentially address issues in my questions/answers.
However, I can't find a trace of the 4-unit loss when checking the
\reputation tab on my profile page. The only item I see for today is the upvote. I also noticed similar inexplicable small reputations losses 2-3 times last summer.
How could I find out where I lost reputation? Is there a bug? Would it make sense to add a "type" display filter for reputation (alongside the existing "post", "time", "graph" displays) that would allow to see reputation changes grouped by categories, possibly corresponding to the cases listed here.