I have just fixed a problem report by swiching back to version 1.7.3.
One of the sheets would have tab 3, cells E1 and F1 would have todays date showing.
The cell formula is a integer (today's date serial value) formatted as a date. (40555 = '12/01/2011').
I tested by setting first sheet sheet cell A1 to 'ZZZ' as the last action before invoking the writer and closing down, with the same result.
I have no idea as to when the change in behaviour would take place as the workbook is full of correct info.
The book has 15 tabs (2 with text, 13 with 11 rows of data, 1 row of heading).
Any ideas ?