Why do you say "It's not that the page hasn't been updated" - I would have guessed it was exactly that, with the html page lagging behind:
For example on the Dynamic CGI generated page
I have 3996 work units completed last uploaded on Sat Aug 17, but on the Static html page
I have 3945 work units completed last uploaded on Wed Aug 7. So it appears the html page hasn't been updated for 10 days, but I don't think that it's abnormal for it to trail like this.