I've been looking at a basic Insights screen. I wanted to see which Hour of Day a particular event was most commonly done. However Mixpanel can't seem to handle this at all - $date seems to be missing as a property.
If I select "All Events" - "Total", I get a nice line chart. If I switch to "All Events" - Aggregate by "Median" for property "Date">"Hour of Day", it says it can't complete the query. Same happens if I use Date in any way - not just Hour of Day. Hovering the Date property shows a description that says "$date" is automatically added to every event. It's a built-in.
Why is this failing? Seems like a bug, but when I reported it Support sent me here.