URDF model included in SDF 1.6 model included in SDF 1.6 world is silently corrupted in Gazebo 11

[traversaro]

When a URDF model is included in a SDF 1.6 model that is itself included in a SDF 1.6 world, and that work is opened in Gazebo 11 from the command line, the model is silently corrupted, in a way similar to #2728 .

Minimal (Not) Working Example

The necessary files are available in urdf_included_in_sdf_1_6_included_in_sdf_1_6_world_mwe.zip, you can setup the enviroment as:

wget https://github.com/osrf/gazebo/files/4656925/urdf_included_in_sdf_1_6_included_in_sdf_1_6_world_mwe.zip
unzip urdf_included_in_sdf_1_6_included_in_sdf_1_6_world_mwe.zip
cd urdf_included_in_sdf_1_6_included_in_sdf_1_6_world_mwe
export GAZEBO_MODEL_PATH=`pwd`

after the environment has been setup, you can run the world gazebo world_sdf_1_6_include_model_sdf_1_6.world and see the problem:

Interestingly, if you use either a URDF model included in SDF 1.6 model included in SDF 1.7 world (world_sdf_1_6_include_model_sdf_1_7.world) or a URDF model included in SDF 1.7 model included in SDF 1.6 world (world_sdf_1_7_include_model_sdf_1_6.world) the issue is not present:

[traversaro]

This issue is similar to #2728, but given that it is not related to the spawning in the GUI at all, I thought that opening a separate issue was more clean. If necessary we can just mark this as a duplicate of #2728 .