I have got a small kink in the needle but its on the very end (probably about .5mm from the end of it). but its fine when there is more paint in the nozzle.
Its when I clean it out that it happens. Its as if the dried paint in the nozzle is blocking the air from coming back. As soon as its clean then it draws the air back.?!
Its a strange one.
The kink in the needle doesn't affect the brush really apart from sometime spraying in funny directions. But I've tried another needle and it still draws air in.