I add to tweak Yarg to add support for multiple pivot tables in multiple worksheets, and in the process I found a minor bug that lead to broken sheet at Excel startup (calcChain problem).
The problem comes from XlsxFormatter::updateFormula : the workaround does not work when you have multiple worksheets.
As I’m very using a very old 1.1.3 Yarg release, here is a file containing the changes I suggest, by using Sheet index instead of 1.
I promise I will upgrade and clone in a very near future.