  Collisions of $^6$Li$_2$ molecules with free $^6$Li atoms reveal a striking
deviation from universal predictions based on long-range van der Waals
interactions. Li$_2$ closed-channel molecules are formed in the highest
vibrational state near a narrow Feshbach resonance, and decay via two-body
collisions with Li$_2$, Li, and Na. For Li$_2$+Li$_2$ and Li$_2$+Na, the decay
rates agree with the universal predictions of the quantum Langevin model. In
contrast, the rate for Li$_2$+Li is exceptionally small, with an upper bound
ten times smaller than the universal prediction. This can be explained by the
low density of available decay states in systems of light atoms [G.
Qu\'em\'ener, J.-M. Launay, and P. Honvault, Phys. Rev. A \textbf{75}, 050701
(2007)], for which such collisions have not been studied before.
