@hisnibs I was just about to report the same problem. Scrolling through the last week of my history, I can see that the date changes from "yesterday" to "today" at 4 pm instead of midnight. That is, it's firing 16 hours too late instead of 8 hours too soon. I suspect the date rollover is hard-coded to Greenwich Mean Time, because I'm eight hours west, in California. I doubt that there is currently a fix for this, and hopefully a future version of Opera will allow us to set a local time zone.
Assuming you use the search box to reduce the number of history links displayed, the incorrect date probably won't prevent you from finding that interesting article you started reading last Tuesday.