[CentOS] Problem with Network devices on boot

hello,

I have a question about network devices ??

on my systems Centos 7.5 I have a Problem with starting Network devices!

I set up two servers with KVM on the first I have 6 KVM installed Systems on 
the second I have 5 KVM installed systems?

When I have to reboot my system  (Kernel update....) the most time one Network 
Device is missing on the KVM Clients (eth0)

I have configured my system with I/O Shared Network like this

xxx.xml

<interface type='hostdev' managed='yes'>
      <mac address='XX:XX:XX:XX:XX:XX'/>
      <source>
        <address type='pci' domain='0x0000' bus='0x03' slot='0x13' 
function='0x1'/>
      </source>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x0a' 
function='0x0'/>
    </interface>

and a second one!
<interface type='hostdev' managed='yes'>
    .........
    ............
This Interfaces are always starting

But I have also a Bridge on the systems (eth0) configure for internal 
Networking (DNS, LDAP.....)

<interface type='bridge'>
   <mac address='XX:XX:XX:XX:XX:XX'/>
   <source bridge='br0'/>
   <model type='virtio'/>
   <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
</interface>

This interface is failing the most  time on some KVM Installs!!

I have always to check is the Interface  starting or not??

AFter 2 or 3 reboot with

virsh reboot xxxxx

the system is starting most time with the third Interface !


Can any tell me why this Problem exist??

Thanks for a answer,
-- 
mit freundlichen Grüssen / best regards,

  Günther J. Niederwimmer