ypbind-1.36-6.fc18 has been submitted as an update for Fedora 18.
https://admin.fedoraproject.org/updates/ypbind-1.36-6.fc18

Package ypbind-1.36-6.fc18:
* should fix your issue,
* was pushed to the Fedora 18 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing ypbind-1.36-6.fc18'
as soon as you are able to.
Please go to the following url:
https://admin.fedoraproject.org/updates/FEDORA-2012-14750/ypbind-1.36-6.fc18
then log in and leave karma (feedback).

I  saw error on upgrading on f17,

  Updating   : 3:ypbind-1.36-6.fc17.x86_64                                                                                                              
/var/tmp/rpm-tmp.2H46WJ: line 7: fg: no job control

I suspect the preceeding whitespace before the %triggerun in else is one possible cause.

%post
%if 0%{?systemd_post:1}
    %systemd_post %{name}.service
%else
    # Package install, not upgrade
    if [ $1 -eq 1 ]; then
        /bin/systemctl daemon-reload >dev/null || :
    fi

    # Package with native systemd unit file is installed for the first time
    %triggerun -- %{name} < 3:1.32-9
    # Save the current service runlevel info
    # User must manually run systemd-sysv-convert --apply httpd
    # to migrate them to systemd targets
    /usr/bin/systemd-sysv-convert --save %{name} >/dev/null 2>&1 ||:

    # Run these because the SysV package being removed won't do them
    /sbin/chkconfig --del %{name} >/dev/null 2>&1 || :
    /bin/systemctl try-restart %{name}.service >/dev/null 2>&1 || :
%endif

(In reply to comment #3)
> I suspect the preceeding whitespace before the %triggerun in else is one
> possible cause.

Thanks for reporting this. I've realized %triggerun shouldn't be in %if block at all, I'm going to submit a new package soon. It should look like as follows:

%post
%if 0%{?systemd_post:1}
    %systemd_post %{name}.service
%else
    # Package install, not upgrade
    if [ $1 -eq 1 ]; then
        /bin/systemctl daemon-reload >dev/null || :
    fi
%endif

# Package with native systemd unit file is installed for the first time
%triggerun -- %{name} < 3:1.32-9
# Save the current service runlevel info
# User must manually run systemd-sysv-convert --apply httpd
# to migrate them to systemd targets
/usr/bin/systemd-sysv-convert --save %{name} >/dev/null 2>&1 ||:

# Run these because the SysV package being removed won't do them
/sbin/chkconfig --del %{name} >/dev/null 2>&1 || :
/bin/systemctl try-restart %{name}.service >/dev/null 2>&1 || :

ypbind-1.36-7.fc18 has been submitted as an update for Fedora 18.
https://admin.fedoraproject.org/updates/ypbind-1.36-7.fc18