See GroupConversionValidationTest.testSeveralGroupConversionsAppliedOnField()

The last assertion in the test fails. The group Complete extends Default and Complex. AFAIU this should cause the validation of the constraints in the groups BasicPostal and ComplextPostal on the Address object, but for some reason all four (instead of the three expected) constraints are invalid, also the one on street2 which is contained in no group.