Parent hostgroup on maps don't display problems of subgroups

Steps to reproduce:

1. create hostgroup AAA/BBB
2. add some hosts to it
3. create hostgroup AAA/CCC
4. add some hosts to it
5. create parent group AAA (no hosts)
6. create map with item "hostgroup" linked to AAA
7. gennerate some problems on hosts in AAA/BBB or AAA/CCC

Result:
Map dislaying OK under AAA group
Expected:
Map displaing Problems of all subgroups.
P.S:
May be this problem has some correlation with my previous ticket ZBX-15853