instance to instance connectivy failures in apex environment

sporadically, in the new jobs using apex snapshots for openstack deployment, we are seeing
instance to instance connectivity failures.

example

Note that the above example is not failing for all of the instances in the test, so the
problem is more isolated. possibly a missing flow or two?

I was not able to find an example of this in our two 1 2 main devstack jobs, so
possibly this is specific to the apex environment.

all logs from the above example