I found the problem, we have a condition when generating DepthBuffers for post processes which is shown on that capture :
Turns out all of these null postprocesses are messing with us.
@sebavan do you remember why we are setting the postprocess reference to null when disposing/detaching in the camera postProcess list instead of just performing splice ? I’m thinking about cleaning all of these null but maybe there is an underlying reason (keeping the order when removing/adding ?)