The Pulse Loader has a quirk- it has a magnet as well as a snap shut lid. The magnet doesn't really come in contact unless you snap the lid shut- which defeats the purpose of having magnets in the first place.
So to "fix" this- take apart the shells- take out the magnet from the back of the shell and super glue it to the top of where it usually sits. Use a small drop of super glue as it'll melt the shell and that is enough to seal it in place
The magnet will now come in contact with the lid's magnet and that should hold a fully loaded Pulse.