Problem with Calculated Columns

Hi

I'm having a problem with calculated columns in a MOSS2007 form library. I put in a formula like:

=[EndDate]-[StartDate]

and it all works fine for a while. It calculates correctly and shows up in the view. Then, after a while, the calculation doesn't work any more. After investigation, it seems that the formula has changed in the definition of the calculated column - the square brackets have been removed, so the formula now looks like this:

=[EndDate]-StartDate

so obviously it doesn't work. After changing it back, it continues to do this - work for a while and then suddenly stop.

It's driving me nuts - please does someone know how to get it to keep the formula.

Thanks,

Glen

[758 byte] By [Glen] at [2008-1-1]