Auto install libreoffice after upgrade

I am not install libreoffice when install system,but after i have a upgrade ,libreoffice are installed,i donot need them,thought i have used YAST forbid
to install OFFICE patterns now,but i want to know why??

It is a recommended application thus is pulled in unless you black list it.

If libreoffice was installed as part of a pattern,
You can’t prevent it from being installed, but it can be uninstalled.