I use application variables a lot on my websites to cache frequently used data

I've just noticed an incredibly odd thing

When I cache the data (once every hour) I use something like this:

      ' Cache all data
      Application("Data_Updated") = Now()      
Now one of my pages was showing some strange results, so I added the following line at the top:

And every time I hit F5 it alternates between two times! i.e.

11/01/2007 16:29:04 and
11/01/2007 16:00:51

Can someone please shed some light on this because as far as I know a variable can only hold one value at a time