Today someone told me their report didn't appear to be updating.
It took quite some digging to find what was happening (since everything was operating normally) but I finally discovered what the problem was.
We were only updating our records for accounts that had already been flagged to appear on a report.
In other words, we weren't keeping up with how people's behaviour might change over time.
So, commenting out a single bone-headed line of SQL (What was my obviously under-caffeinated brain thinking? What?!? What??!), and voila, everything is now as it should be. It means reports will be slightly slower (in this case, this is a good thing) - but only because we'll now be pulling down much more information from Twitter, which takes time.
The upshot of this? Your reports will now have much, much more detail on them. I ran it on my personal account (@sidawson) and my report went from having 47 people on it to 190 (I've been deliberately leaving them there so I can test the new version)
If you've run a report in, ohh, the last few months, might be worth running it again now.
My apologies for not noticing this sooner. It's all very silly.