StihlMS880 air filter problem

[Derwentmole]

Can anyone advise please? I recently bought an HD filter as a spare for my 880(2007)which included a foam insert. The filter that came with the saw is green and doesn't have the foam insert(just fine mesh?). I took the green filter off to clean it and noticed quite a bit of fine dust had bypassed the fine filter. No holes in it etc. I don't use the saw a great deal at all and only for milling the odd bit. I replaced the Filter the new hd2 filter(with green foam insert)for quickness but it just wasn't running right as seemed not to be getting enough air and bogging down when cutting. Spoke to a local tree surgeon who said its a problem with the Stihls? I also read somewhere to take the box off and have the filter sitting on the outside uncovered? Any idea how best to proceed or suggestions on filters would be much appreciated. I could do without a blocked/nackered carb if poss. Sorry haven't got pics but found a couple on line and just hoped someone might know what I'm on about. Thankyou.