Pretty minor bug, but whenever you're viewing the Web Service Activity log (unsure if this effects other logs – haven't tested), you're unable to filter by a specific request date:
This yields no results despite having plenty of web service activity for that day.
This happens with any date you choose to filter down to.
Whenever you use another equal-to operator, e.g. LTE, it shows dates from the previous day and on. So for some reason, the equal-to operator just isn't working even for other comparison operators.
I've tried this in two different APEX instances with different workspaces and still encountering the same issue. Mainly just a minor annoyance, I don't think this would ever cause any impedance in the slightest.