Incorrect date grouping in sidebar for previous builds

When viewing this build version for the PHP driver, I noticed that the sidebar listing previous builds incorrectly grouped builds from the previous day under a title for the current date (Feb 20). If you look at the attached screenshot, the first build for Feb 20 should be cdc8b. Build 30a84 and those following should be grouped under a Feb 19 title. The builds do appear to be ordered correctly by their timestamp. I expect the problem is just that everything from the previous 24 hours is being grouped under the current day's title. It will be interesting to see if a Feb 19 title shows up after 7:22pm once 1de89 exceeds the rolling 24-hour window.