I just checked on the server and ya things had gotten stuck on the dashboard. I just restarted that process so it should work again now. There's obviously some server-side bug that I haven't trapped yet.
You can look at the download tool source code here. The code that pulls data from OpenSensors.io is all contained in this file, and the code that stitches the data from the different sensors together is located in these lines of code. I think it does a pretty good (much better) job of aligning the data records in time since I updated it 12 days ago, I'll probably re-write the whole download tool again at some point in the future to be less RAM intensive. If you are interested, the code for the experimental dashboard is also available for review here.