The paper "Kant's conception of Berkeley's Idealism" by G.J Mattey says that
(1) Leibnitz argument in defense of what Kant called dogmatic Idealism in the Politz lectures on Metaphysics in the late '70s, stated that "bodies are pure appearances" and "I acknowledge thinking beings of which I have an intellectual intuition, thus [dogmatic idealism] is mystical."
(2) Leibnitiz's argument holds that bodies cannot be real beings, because their nature conflicts with what i known to be characteristic of reality, in this case, thinking monads. The natures of body as extended implies that they are infinitely divisible, which contradicts the simplicity of monads.
(3) The intellectual notion of monads is crucial to the argument, since there is no inherent conceptual absurdity in supposing matter to exists on the view of Leibniz expounded by Kant.
(4) For this reason the dogmatic conclusion about bodies rests on mystical premises, so that Kant could equate dogmatic and mystical idealism.
But this argument seems strange. It looks like there is no explicit reference to Leibnitzian monads when Kant expounds the dogmatic Idealism as (3) says, but we now for certain that he was well-aware of the problem of monads since he himself had worked on it previously on Physical Monadology. The paper's claim that Kant's claim that dogmatic idealism rests on mystical premises is given because of the omission of Leibnitzian monads doesn't quite fit what we already know about Kant and his writings on Newtonian vs Leibnitzian space.
The most obvious answer one has in mind is that Kant didn't consider monads because he rejected their existence, but doesn't the very same argument applies once we replace Leibnitizian monads with Kant's point-like monads?