Ring group to external cid problem

Hi, I have a ring group setup that should call an external number if the first group does not answer. Does not seem to be working as expected.

When a call is entering the system from outside and it is directed to a ring group lets call it “Level1”. Level1 has member 2 extensions:
101
102
if nobody answers for 20 seconds “Destination if no answer” is another ring group “Level2”. Level2 has member 2 extensions and 1 outside number:
101
102
YYYYYYYYY#
Everything works except that YYYYYYYYY# is unable to go out throught the trunk. The call is not going out as if there was a outgoing CID problem. However if I edit ring group “Level1” that way:
101
102
YYYYYYYYY#
… it works. The call is going to a mobile backup number(YYYYYYYYY#) outside correctly.

In both ring groups I have setup:
Change External CID Configuration Mode:
Fixed CID Value Fixed
CID Value: WWWWWWWWW (some valid Trunk number)

My conclusion is that something is broken if the group is called from another group.

Reassuming:
Inbound route -> ring group [including and external number WWWWWWWW# ] -> works OK call reaches WWWWWWWW#

Inbound route -> ring group 1 -> ring group2 [including and external number WWWWWWWW# ] -> do not work - call does not reach WWWWWWWW#

FreePBX 2.11.0.16
ps. should I post some logs / tcpdump ?