Which version of Tableau are you on?
Tableau support has suggested I update and see if the problem persists. Which I can do, it's just a bit of a process as I will need to update the reader for anyone trying to view it.
It's just really odd since they've been working all year long and now all of a sudden are having issues. I did just eclipse 1 year's worth of data so I'm not sure if/how that would have an effect.
Ah, this well may be the case with early 9.x releases.
I've got a couple of cases with my customers
regarding calculations & extracts (all went haywire).
The problem(s) were workbook-specific --
wrong internal references to calcs / parameters.
And I had not even been able to trace them to the origin(s),
not to mention reproducing them in a clean sample wb.
The suggestion is to work on a case
together with the Tableau Support people.
By the update they mean upgrading
to the recent version of 9.3.x, I hope.
You could even install it side-by-side
with your current one and use both.
Your colleagues with a Reader
don't need to upgrade.
here is the link to the download page:
If you don't mind sharing the workbook
(and I doubt you do), I would like to help.