Based on available information till date, we cannot say why ISX was suspended. All we know is ASIC is looking into disclosures after ASX referred ISX, it could be to do with performance shares, but we can't say with 100% certainty. If its to do with performance shares, all ASIC needs to do is call this out and investigate it forensically. Not hard with all the power and resources at hand. But preempting this and therefore handing over the shares before any evidence is presented is premature and could have ramifications to JK's position and also ISX.
We need to also keep things into perspective. The event you/we are raising happened in Aug/Sept 2018. Further, we are also questioning the integrity of the auditors who would have followed through strict compliance norms related to the issue of performance shares at that time. In my view, the situation on hand is far too complicated.
ASX, in my view, went beyond their powers to suspend ISX. A court case is/was the only way to get to the bottom and not a gesture of goodwill to hand over shares.