this playground https://www.babylonjs-playground.com/#9QQ97W#1 doesn’t work with cannon physics and current latest (v4.2.0-alpha.17). It seems that the ground-plane gets rotated when assigning the impostor. If you switch to 4.1.0 it works fine. On my local dev-environment it even works with v4.2.0-alpha.16.
I’ve noticed there was a commit to cannon plugin
src/Physics/Plugins/cannonJSPlugin.ts a couple of days ago maybe this has something to do with this issue.