Pivot Table replay edits does not propagate if column headers change

[aarondr77]

1. Create a pivot table
2. Add a formula like, LEFT(value from pivot table column)
3. Update the aggregation type of the pivot table
4. The formula disappears

This is hard to handle without either adding A, B, C, ... ways of referencing columns or saving the column ids from the original pivot table, re-using them based on index in the pivot table, and saving the formula to use column ids