I stand corrected. Again.
And here I was finally hoping to have found a good example of where intuition misleads us... well, it doesn't. If the mass is dropped from the fuselage, then indeed as others have said, the load on the wing-fuselage junction will in fact decrease momentarily. If, however, the mass is dropped from the wings, then the load on the wing-fuselage junction will momentarily increase. In both scenarios the physics follows intuition.
Uplinker because gravity is not a constant but a function of where in XYZ space you are located, it is scientifically inaccurate to refer to the weight of an object without also knowing what the local conditions of the gravitational field are - hence mass being the preferred term. Interestingly, this varies by about 0.7% on the surface of the planet (owing to different rock densities in earth's crust), and of course decreases as you gain altitude and go further away from earth's surface. Other bodies like the moon and the sun play a role as well, and not an insignificant one (c.f. the tides). So, a 1kg mass on a mountain in Peru will measure about 995 grams on the same scale it reads about 1005 grams at the surface of the arctic ocean.
In aviation world, this is often evidenced by the "pragmaticists" in FAA world who for example refer to maximum take of weight (MTOW). Whereas in the "idealist" EASA lands, the same number is referred to as maximum takeoff mass (MTOM).
Just an interesting sidenote...