Formula/Link breaking when any changes are made

Good morning,

I have created one workbook that has multiple links to other workbooks. Typically they use SUMIF functions to add values from multiple sheets within workbooks.

The problem is this. On the surface, the formulas and links seem to be working properly. However, if I add a column or try to copy the sheet (Edit - Move or Copy Sheet), all of the cells containing formulas change to "#VALUE"

Any suggestions?