Hi @eloi3
The IMX219-83 Stereo Camera is not a synchronized camera and the output from the two camera is not synchronized. This is the reason Isaac ROS vslam is not working with this camera input.
A good reference for choosing your camera for Isaac ROS vslam is available in this post: Choosing camera to start my project using VSLAM - #2 by clementchiengcze
Best,
Raffaello