Very interesting indeed.

I checked my stats, they were almost 48 hours out of date when I was running the query yesterday (and have not been updated as of yet). There are about 40,000 rows added to this table on a daily basis and its has over 13 million rows in total.

The thing is, the filter on my query looks at the last 3 months but starting at the 1st of the month. So its not concerned with the last 11 days.

I'm still confused...