Custom URDF not being imported properly


I am trying to build a image dataset using multiple URDF robots in Omniverse using Replicator. I have been trying to explore different ways, one by first importing the models and creating a USD file which I shall use for replicator python scripting, and one directly importing using python script.
However, when I import the models, by URDF importer or through python script, I face the same problem of robot links not being connected properly. The RPY angles mentioned in the URDF changes arbitrarily for some of the links when checked through the Isaac Sim UI. This shows the robot wheels in correct orientation but the chassis is rotated by 90 degrees(same for other small parts).
This has happened with 3 different URDF models that I tried with.
Please share what could be the problem in my approach since even through the extension, I face the same issue.

Thank you.