[exim] Hosts_randomize inconsistant ?

I have been pulling my hair out about this for a couple of days, and here is
what I have found - which I believe is inconsistant behaviour in Exim.

Firstly host_randomize=true in routers.

delivery:
driver = manualroute
dsn_process
transport = remote_smtp
hosts_randomize = true
route_data =
md01.swi.test.net:md02.swi.test.net:+:md01.pr.test.net:md02.pr.test.net

remote_smtp:
driver = smtp
connect_timeout = 1m
hosts_avoid_tls = 196.168.0.0/16
multi_domain = false

The results of this are that a new delivery is started for each recipient
even if the user is in the same domain (multiple => lines)

Now, if we change the hostnames for IP addresses....

delivery:
driver = manualroute
dsn_process
transport = remote_smtp
hosts_randomize = true
route_data = 192.168.1.1:192.168.1.2:+:192.168.2.1:192.168.2.2

remote_smtp:
driver = smtp
connect_timeout = 1m
hosts_avoid_tls = 196.168.0.0/16
multi_domain = false

This works perfectly fine !! (1 => followed by multiple ->)


But, lets move the hosts_randomize from the router to the transport :-

delivery:
driver = manualroute
dsn_process
transport = remote_smtp
route_data = 192.168.1.1:192.168.1.2:+:192.168.2.1:192.168.2.2

remote_smtp:
driver = smtp
connect_timeout = 1m
hosts_randomize = true
hosts = 192.168.1.1:192.168.1.2:+:192.168.2.1:192.168.2.2
hosts_avoid_tls = 196.168.0.0/16
multi_domain = false

This time, it completely forgets that I even have the + in there to group my
lists and just picks any at random (though it does at least do them all down
one connection - I didn't try with hostnames here)....

For info, the hostnames & ip's forward and reverse resolve in DNS so they
are technically equal.

-Andy-