That is the nature of the location of the filter. Specifically using a Sprinter air filter will eliminate the sand getting past the filter but sand will collect in the filter itsself. The location of these filters are almost like making it a bucket. The Sprinter material is said to be waterproof as well as sand cant get past them. The cotton gauze filters will let water and sand(to a certain extent) past due to the material used. The V2 Starace has the added velocity finn's that help prevent contamination bit at the end of the day the assembly is focused on performance and you will still get some debris. To help combat the issue. Under the steering tube you will see the frame welded in a triangle. The center of that triangle is a direct path for debris coming off the front tire up to the air filter. If you are riding in rain or dirt roads you could put a piece of tape over that triangle. It definitely helps. I dont do it all the time, only when I plan on extended time in dirt or rain.
