[R] Downloads -- possible bug?

[Elizabeth Purdom]

Hi,
When I go to the CRAN page to download a new version of R, there are not 
the same versions available depending on which mirror I pick. When I go to 
http://cran.cnr.berkeley.edu/, for example, I get 2.2.1, but if I go 
http://cran.stat.ucla.edu/ the option is 2.2.0 (I'm downloading the Windows 
base file). Neither refreshing nor clearing my cache changes it. For future 
reference, I'd like to know if this is a mistake or if different mirrors 
are just updated at different times?
Thanks,
Elizabeth Purdom