Mobile robot jumps forward at the start of simulation

So I imported the robot’s URDF to import the body of my robot. The spherical wheel could not be imported so I had to add one by hand with the same characteristics and also to create the joints by hand. The problem now, as can be seen in the video, is that when I start the simulation the robot “jumps” forwards instead of “dropping” normally. How can I fix this problem, and also the warnings from the console to progress into ROS2 development and RL.

video link:

I could notice from the UI that the joints contains a red circle in their icon - This means that the joints are not properly aligned in the asset. In the first simulation step it will resolve those broken poses, and that will cause rigid bodies to gain some velocity - That’s what makes the robot move in a weird way.

Can you try resolving the joints Relative poses so it clears those red circles?