sometimes / sometime / some time
The English language does not contain the word ‘sometime’ (although it can of course be used in poetry, where anything is allowed: “Sometime too hot the eye of heaven shines …” Shakespeare).
Mae West declared, “Come up and see me some time” meaning come up and see her one day or at some juncture in the future and, as you point out, implies one occasion (although it does not preclude subsequent occasions).
PR