"Convert to Formula" infos get lost

Dear experts,

I have a workbook with SAPGetData formulas in it. This way, I can use the Query (full crosstable), but at the same time, pick some special fields, without having to reference them in Excel hardcoded (more flexible, if query changes or user navigates).

The workbook works fine and fulfills all needs of the user.

BUT. Sometimes he needs to save the file locally, add some information or send it to a recipient outside the company.

When he saves the workbook as regular XLS-File (or XLSM-File), enters some new data to the file and sends it via E-mail. The data disappears (sometimes). There is no error or any sign like 'N/A' in the fields. The cells are simply empty. This concerns only the SAPGetData-fields - the data in the crosstable however stays in place.

We work with Microsoft Office Project Profesional Plus 2013 and Analysis for Office 2.3

Is this just a bug (e.g. of Analysis or Excel)? Because sometimes (especially within the company) it works fine!

I'm gratefull for any advice.

Thank you!