Is this your first airhead, Chris? They shift different from Japanese-type clutches (wet, multi-plate), if that is what you are used to.
Like Justin said, a little preload, and don't be in a hurry. I nearly always miss that shift if I get in a hurry and forget about technique.
And don't ignore that spline lube, if you have not checked it out since purchasing the bike.
but, since this is an increasing frequency event, it could be more serious.