Echo CS 510 dust under filter

[Yellowdog]

I recently looked under filter on an Echo cs510 that I took back from an employee. I saw a lot of dust inside the carb throat and around the mouth of the throat. I cleaned it up and checked the filter. This saw probably has 20 hours on it. Is this normal or do you think the filter was not on secure. I couldn't find a problem with the filter. any thoughts?