1. Open or create XLS or XLSX file and enter date with Czech format "DD.MM.YYYY", for example 01.02.2017.
2. Save file and open in in Microsoft Excel or upload it to Google Documents.
3. Such cell will be displayed with "MM.DD.YYYY" format (02.01.2017).
Note: "D. M. YYYY" format works fine and is displayed correctly in LibreOffice Calc, Microsoft Excel, and Google Documents.
It seems like a bug in Calc to me.
*** This bug has been marked as a duplicate of bug 113889 ***