The obligation to disclose is contingent upon the officer in charge forming a view whether its material or not. If immaterial eg. Someone tweets ASX's aircon is too cold - there is no obligation to disclose.
As posted above...
And this part in particular
My point being the stock did not move at all vindicates the decision to ignore. If the ASX dropped 10% then we wouldn't be having this discussion
ISX Price at posting:
$1.07 Sentiment: Sell Disclosure: Held