  The aim of the paper is to correct and improve some results concerning
distributional chaos of type 3. We show that in a general compact metric space,
distributional chaos of type 3, denoted DC3, even when assuming the existence
of an uncountable scrambled set, is a very weak form of chaos. In particular,
(i) the chaos can be unstable (it can be destroyed by conjugacy), and (ii) such
an unstable system may contain no Li-Yorke pair. However, the definition can be
strengthened to get DC$2\frac{1}{2}$ which is a topological invariant and
implies Li-Yorke chaos, similarly as types DC1 and DC2; but unlike them, strict
DC$2\frac{1}{2}$ systems must have zero topological entropy.
