CaF2 partially dissolves into Ca2+ and 2F-.
CaSiO3 partially dissolves into Ca2+ and SiO3, but there's already some Ca2+ in solution, which prevents as much of this from dissolving. SiO3 dissolves with Ca2+ in this way in a 1:1 manner, but since there's already some Ca2+ in solution, [Ca2+] > [SiO3].