It's best practice to ensure the inner sleeve reaches to the middle part of the Capsi capsule when closing the lever. You'll need to apply more than normal force to close the cover of your capsule machine when using Capsi. This is simply because Capsi is made entirely of stainless steel (including the lid), whereas most single-use capsules are made from Aluminium or plastic. With correct use, Capsi will not damage your machine.
For correct capsule placement within your machine, please check out this video.