I have several others VMs in the same host, pretty much identically configured, all are fine, all on the same bridge:
mini@ykaul-mini:~/ovirt-system-tests$ sudo brctl show
bridge name bridge id STP enabled interfaces
5e85-930e31b 8000.525400247745 yes 5e85-93031b-nic
vnet0
vnet1
vnet2
vnet3
vnet4
virbr0 8000.5254005e7e4b yes virbr0-nic
virsh # net-dumpxml 5e85-930e31b9b9
<network connections='5'>
<name>5e85-930e31b9b9</name>
<uuid>6f52f5a8-5322-4b57-890e-d4d5a0a7ed50</uuid>
<forward mode='nat'>
<nat>
<port start='1024' end='65535'/>
</nat>
</forward>
<bridge name='5e85-930e31b' stp='on' delay='0'/>
<mac address='52:54:00:24:77:45'/>
<dns forwardPlainNames='yes'/>
<ip address='192.168.200.1' netmask='255.255.255.0'>
<dhcp>
<range start='192.168.200.100' end='192.168.200.254'/>
<host mac='54:52:c0:a8:c8:04' name='lago_basic_suite_3_6_host1' ip='192.168.200.4'/>
<host mac='54:52:c0:a8:c8:03' name='lago_basic_suite_3_6_engine' ip='192.168.200.3'/>
<host mac='54:52:c0:a8:c8:02' name='lago_basic_suite_3_6_storage-iscsi' ip='192.168.200.2'/>
<host mac='54:52:c0:a8:c8:05' name='lago_basic_suite_3_6_storage-nfs' ip='192.168.200.5'/>
<host mac='54:52:c0:a8:c8:06' name='lago_basic_suite_3_6_host0' ip='192.168.200.6'/>
</dhcp>
</ip>
</network>
Domain XML attached.
Running libvirt 1.2.18, on latest F23.
Y.