After Effects won't render a 3d model with shadows enabled on Studio M1 Ultra

I'm trying the new After Effects 3d model import workflow on my Studio M1 Ultra and when I import a 12mb .glb model it all works fine.

However, when I include environment light with cast shadows enabled and create a shadow catcher, the shadow appears for the first frame but then the render is stuck and doesn't render any of the remaining composition. Fast scrubbing along the timeline sometomes renders a frame or two but I switch to Draft 3d mode to be able to render the composition and the shadow is completely gone.

Finally, when I want to do a final render of the whole composition, the rendering process takes forever and the progress bar (both in AE and MEdia Encoder) doesn't move at all, even after 30min trying to render a composition that is 30s long. When I deisable shadows completely the rendering works as expected.

I know that the Studio Ultra M1 is no super computer but I I was al least expecting to be able to render shadows on the lowest setting. Also, I have no issues with renderinmg more complex models with shadows in Blender. 

Can somebody explain what is happening? Is is a matter of tewaking settings or I just won't be able to render shadows on my machine at all.

Thanks for your help!