The column order was being incorrectly reset in a variety of circumstances:
Whenever the value of a variable used in a filter is changed. (FC-3206)
When the report is opened, if variables are being used within 'Allowable Value Columns'. (FC-3198)
When editing the filter of a dimension which is pivoted across, even if the selections are not changed e.g. inserting a space. (FC-3207)
After visiting the Add/Remove Filter dialog and making changes that shouldn't affect column order, and the column headers in the grid aren't updated. (FC-3214)
After visiting Member Selection dialog of connection or across dimension filter and clicking OK without changing anything (FC-3219)
An error would occur in the Edit Bucketing dialog if you added a bucketing dimension and then immediately clicked the Move Up or Move Down buttons. (FC-3169)
A calculated dimension which produces numeric results could return the result from another row, if the numbers were the same apart from the position of the decimal point. (FC-3217)
The column order gets reset when running a report after re-opening the workbook. (FC-3203)
A new planning scenario could be selected in the Excel Add-In but couldn't be submitted to until the report or workbook was re-opened. (FC-3201)
The member selection dialog for the filter of a variable sometimes failed to show any members. (FC-3225)