We investigate the connection between $\triangle^1_3$-stability for random and Cohen forcing notions and the measurability and categoricity of the $\triangle^1_3$-sets. We show that Shelah's model for $\triangle^1_3$-measurability and categoricity satisfies $\triangle^1_3$-random-stability while it does not satisfy $\triangle^1_3$-Cohen-stability. This gives an example of measure-category asymmetry. We also present a result concerning finite support iterations of Suslin forcing.