That's just dirt, so no need to worry. Usually you have to replace those filters every 12k-18k anyway, so at 20k it definitely needs to be replaced. Nothing to worry about at all.
Actually, many intake systems routinely suck in a bit of oily vapor from the PCV (crankcase ventilation) systems. Depending on the flow of air across the filter housing, this could account for the pattern in the original post.It's the same stuff you breath in everyday.
OMG, And just when I thought the Coronavirus was bad Glad we live in the country. All we breathe in are diesel tractor fumes and crop chemicals.It's the same stuff you breath in everyday.
Honda OEM filters (if this is one) have a light coating of oil to trap particulates and this look is absolutely normal. I change mine every 20k and it looks just like that.