Description of problem:
Setting up a system with systemd-networkd for networking, I receive the following errors in the logs:

# journalctl -u systemd-networkd
...: Could not emit changed OperationalState: Transport endpoint is not connected
...: Not connected to system bus, not setting hostname.

The same services worked correctly in Fedora 27.

It's likely that systemd-hostnamed is also affected, although I don't have it configured on my system.

Version-Release number of selected component (if applicable):
systemd-238-8.git0e0aa59.fc28.x86_64
selinux-policy-3.14.1-24.fc28.noarch

Additional info:
----
time->Wed May 16 15:24:08 2018
type=PROCTITLE msg=audit(1526509448.216:82): proctitle="/usr/lib/systemd/systemd-networkd"
type=PATH msg=audit(1526509448.216:82): item=0 name="/run/dbus/system_bus_socket" inode=22634 dev=00:17 mode=0140666 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:system_dbusd_var_run_t:s0 nametype=NORMAL cap_fp=0000000000000000 cap_fi=0000000000000000 cap_fe=0 cap_fver=0
type=CWD msg=audit(1526509448.216:82): cwd="/"
type=SYSCALL msg=audit(1526509448.216:82): arch=c000003e syscall=254 success=no exit=-13 a0=f a1=555fce7fd110 a2=2000d84 a3=7562642f6e75722f items=1 ppid=1 pid=421 auid=4294967295 uid=192 gid=192 euid=192 suid=192 fsuid=192 egid=192 sgid=192 fsgid=192 tty=(none) ses=4294967295 comm="systemd-network" exe="/usr/lib/systemd/systemd-networkd" subj=system_u:system_r:systemd_networkd_t:s0 key=(null)
type=AVC msg=audit(1526509448.216:82): avc:  denied  { read } for  pid=421 comm="systemd-network" name="system_bus_socket" dev="tmpfs" ino=22634 scontext=system_u:system_r:systemd_networkd_t:s0 tcontext=system_u:object_r:system_dbusd_var_run_t:s0 tclass=sock_file permissive=0
----
time->Wed May 16 15:24:08 2018
type=PROCTITLE msg=audit(1526509448.223:83): proctitle="/usr/lib/systemd/systemd-resolved"
type=PATH msg=audit(1526509448.223:83): item=0 name="/run/dbus/system_bus_socket" inode=22634 dev=00:17 mode=0140666 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:system_dbusd_var_run_t:s0 nametype=NORMAL cap_fp=0000000000000000 cap_fi=0000000000000000 cap_fe=0 cap_fver=0
type=CWD msg=audit(1526509448.223:83): cwd="/"
type=SYSCALL msg=audit(1526509448.223:83): arch=c000003e syscall=254 success=no exit=-13 a0=f a1=55817d0ce9d0 a2=2000d84 a3=7562642f6e75722f items=1 ppid=1 pid=498 auid=4294967295 uid=193 gid=193 euid=193 suid=193 fsuid=193 egid=193 sgid=193 fsgid=193 tty=(none) ses=4294967295 comm="systemd-resolve" exe="/usr/lib/systemd/systemd-resolved" subj=system_u:system_r:systemd_resolved_t:s0 key=(null)
type=AVC msg=audit(1526509448.223:83): avc:  denied  { read } for  pid=498 comm="systemd-resolve" name="system_bus_socket" dev="tmpfs" ino=22634 scontext=system_u:system_r:systemd_resolved_t:s0 tcontext=system_u:object_r:system_dbusd_var_run_t:s0 tclass=sock_file permissive=0

I added the following rules and the errors in the logs were resolved (I'm not sure if write access is also required though!):

#============= systemd_networkd_t ==============
allow systemd_networkd_t system_dbusd_var_run_t:dir read;
allow systemd_networkd_t system_dbusd_var_run_t:sock_file read;

#============= systemd_resolved_t ==============
allow systemd_resolved_t system_dbusd_var_run_t:dir read;
allow systemd_resolved_t system_dbusd_var_run_t:sock_file read;