You let too much liquid evaporate out of the airlock, exposing the gaps at the bottom of the middle "hat" piece. This means you almost certainly now have mold spores in the beer itself, which in turn means it's just a matter of time before you see mold growing on the surface of the beer (if it's not already). If I were you, I'd sample the beer, and if it tastes ok, package it now, or at least cold crash it to retard the inevitable mold growth. Having mold in the airlock in the first place means that there was food in it, i.e. carbon (sugars), probably left over from a previous, explosive krausen that pushed through the airlock(?). I'd soak that airlock in hot PBW before using it again.