So every time i turn on motion blur on a render where there is physics involved i get this weird artifacts. The physics are baked. at first i thought it was my awkward workflow with alembic but it started happening even with vanilla blender baked physics. the only way to fix it is either turning off motion blur or lowering the shutter speed
it only happens on certain frames. it’s easy to fix when it’s just 3 or 4 frames but sometimes i have it on every other frame completely destroying the render