Issue selinux-policy targeted yum update error

[Umberto Bellotti]

During yum updateof SELinux on CentOS 6.9 the following error appears (it is an already known error since about 2014):

/etc/selinux/targeted/contexts/files/file_contexts: Invalid argument
libsemanage.semanage_install_active: setfiles returned error code 1.
semodule: Failed!

I'm unable to retrive updated information about this issue on the Internet.
Many thanks for help.