-1 shows up when importning Excel tables with formulas containing text

Hi there,

I have problems when I import tables from Excel to Indesign. The tables in Excel contain formulas - when the formula results in numbers, there are no problems but when the formula results in text, the "-1" will appear in the cell in InDesign. 

Does anyone know how to fix this (if it is fixable)? 

I know it is possible to make the values in Excel static and then import the table. However, the Excel tables are updated regularly so it is important to me that I can link properly between the Excel-file and the InDesign-document without having to do a lot of manual work for instance in the Excel-file. 

Thank you in advance.