The problem is that when I grab an object and move with the joystick, the object doesn’t stay in the hand. I have set the parent to the hands, and the object’s world position is equal to the hand’s world position. Similarly, I have set isKinematic to true. Also, when I place a rigidbody on the hand and start moving with the joystick the hand, it has a strange movement.
Hey 
Can you share more about your implementation.
Is that hand of the controller that you get?
Or is that the hand of the custom WebXR Avatar?
Ideally if you could share a video, that would be best.
Even better if you could share also a build 
I hope we can resolve your issue 
Hi, thanks for answering. The problem I have is with the custom XR Avatar, and I do have some videos showing the error, but I can not upload them here
Can you upload the video via imgur, wetransfer or google drive and share a link?
Hi, of course, here are the two examples I mentioned to you
sorry this one is the other example