Group columns does not work!

I group columns as long as I have the file open is ok. I save and exit the file, when I enter the file again, group columns does not exist and all grouped columns are hidden.
When I group rows everything is ok.
What can I do? Please help!

What LibreOffice version, file type and OS?

LibreOffice Version: file type xlsx and OS Ubuntu 14.04 LTS - Any ideas? Please!

I can reproduce the issue with 5.1.6 on windows, but looks solved with 5.2.6.

Can you update your version?