Invoice number being converted to date field when exporting to CSV or viewing in Zoho Sheet

Invoice number being converted to date field when exporting to CSV or viewing in Zoho Sheet

We have a serious problem.   We currently use a prefix of "11-" and then use auto generation of invoice number.  For example the complete invoice number would be "11-5983".   When we export the invoices to CSV or view in Zoho sheet it converts these invoice numbers to a date field.  We need a fix for this.