InterfaceAddWorkerOnElan:setElanBCGrouponOtherDpns method installs full BC group on all DPNs that are related to an ELAN. This method has a Thread.Sleep() call inside a loop iterating the DPNs, with default of 300ms sleep per loop iteration

In a scale setup, with dozens of DPNs, this delays significantly the call to InterfaceAddWorkerOnElanInterface, which in turn installs table52 "output to full BC group" flow.

In the mean time, vms that are spawning, which are the first ones on their compute nodes, are dependent on the above flow to send their DHCP "discover" packet. consequent of that some of them gives up attempting to obtain IP ,before the above flow is installed.