TF tree has multiple parents for the 'odom' node

[sayali-purdue]

The launch file onboarding_simulator.launch contains two args:
<arg name="3d" default="false"/> <arg name="single" default="true"/>.

If the value of arg 3d is set to true, then this launch file would invoke the launch file called sim.launch, which in turn would invoke the launch file called sim_single.launch (as the value of arg single is true).

The launch file sim_single.launch publishes a static transform from frame_id drone/odom to child_frame_id odom at line 30.

However, the launch file onboarding_simulator.launch also invokes another launch file called backbone.launch, which publishes a static transform from frame_id map to child_frame_id odom at line 9.

This results into a TF tree with multiple parents for the odom node (parents: drone/odom, map). The tree representation can have only one parent for each coordinate frame (REP-105). Therefore, this seems to be an issue during 3d simulation with single configuration.

Could you please confirm if my understanding is reasonable? Would really appreciate if you could provide your thoughts on the above observation.

Thank you!