Why some vms are getting two ips assigned while launching 50+ vms in a batch?

Issue

• When launching more than 50+ instances in a batch (from Horizon -> instance count 50+), some of them have two private IP's associated to one nic.

Nova shows also says the same. Eg,

nova show 0967af75-c7ef-421a-a91b-5dcccc8b53c6
                                                  |
| private_managment network            | 192.0.3.64, 192.0.3.37                                   |

and /var/lib/neutron/$networkid/dhcp/host shows 2 different mac addresses with their IP's

fa:16:3e:33:8f:57,host-192-0-3-64.openstacklocal,192.0.3.64
fa:16:3e:26:bb:f4,host-192-0-3-37.openstacklocal,192.0.3.37

But inside the machine only one interface is available which is configured with either of them.

How can I resolve this?