I think there was a bug in the addHullVerts and addMeshVerts methods where they weren’t properly setting rotation. Based on this thread btBvhTriangleMeshShape questions - Real-Time Physics Simulation Forum ammo’s btBvhTriangleMeshShape should only be used for static bodies.
I will create a PR (fix rotation for meshes and fallback to convexMesh when mesh impostor… by TrevorDev · Pull Request #5978 · BabylonJS/Babylon.js · GitHub) to fix the rotation, I beleive it will make cylinder impostor and convex hull work as you expect. For mesh impostor, maybe I should check if mass is not 0 and create a convex hull instead in that case to get the expected behavior for that case.