This issue is triggered by the configuration of the spreadsheet application that you are using. You need to configure your spreadsheet application to keep the zeros at the beginning of numeric values. The option for this is usually found in the cell formatting section of your spreadsheet application.
Microsoft Office KB: https://support.office.com/en-us/article/Keeping-leading-zeros-and-large-numbers-1bf7b935-36e1-4985-842f-5dfa51f85fe7
LibreOffice KB: https://help.libreoffice.org/Calc/Entering_a_Number_with_Leading_Zeros