It is reported that iodine forms compounds like $\ce{(CH3COO)3I}$, $\ce{I(ClO4)3}$ and $\ce{IPO4}$ which contains $\ce{I+}$ and $\ce{I^3+}$ and are not bonded covalently as in interhalogen compounds.
Generally, Halogens form anions of the type $\ce{X-}$ to achieve stability by attaining noble gas configuration. However iodine loses electrons when it forms a cation and does not attain noble gas configuration. So why does iodine form cations while no other halogen does?