I have a 75+ worksheet 2003 workbook that recently stopped reliably updating
linked formulas and recalculating function formulas. "CALCULATE" appears in
the status bar although the the spreadsheet option is set to automatically
calculate. Ctrl Alt F9 and F9 do not seem to force a recalculation.

Editing the formulas, for example, by changing instances of "=" to "a=" and
then edit back from "a=" to "=" will force spreadsheet to recalculate the
edited formulas.

Is there a reason for this behavior? I am baffled!