This bug was fixed in the package network-manager - 1.2.6-0ubuntu0.16.04.2
--------------- network-manager (1.2.6-0ubuntu0.16.04.2) xenial; urgency=medium
* Fix nm-dhcp-helper DBus Event/Notify race condition (LP: #1696415)
-- Ray Link <email address hidden> Thu, 19 Oct 2017 13:53:52 -0400
This bug was fixed in the package network-manager - 1.2.6-0ubuntu0. 16.04.2
--------------- 0ubuntu0. 16.04.2) xenial; urgency=medium
network-manager (1.2.6-
* Fix nm-dhcp-helper DBus Event/Notify race condition (LP: #1696415)
-- Ray Link <email address hidden> Thu, 19 Oct 2017 13:53:52 -0400