Is it just the loaded artifact class that can't pick up a monster summon charm or what? I can pick up any other charm, though it doesn't add two of it, but I've even tried dropping some of my droppable charms and still can't pick up a monster summon charm.
My character skin -
http://skincity.beyondunreal.com/?section=skins&action=show_infos&id=1513
or
http://www.utzone.de/include.php? path=content/download.php&contentid=4280
http://friends.GameFly.com/r/5c9eec123614102a919d
My Loaded Weapon character is known as [DC]FodderFigure My medic character is known as [DC]FodderFigure_MD My Artifact character is known as [DC]FodderFigure_LA
For some reason LA just can't pick up items until the exact moment they disapear... actually now that I think about it I'd guess it might not be LA but the Loaded Artifacts skill that does it.
The ability to squat over an artifact or have one thrown directly at you is technically a bug; you basically need to "get" the artifact as it is "spawning" or as it disappears.