My suspicion on this is that the flight was legal, right up to the point where the pilot decided to continue the planned flight rather than divert due to weather. However, it was only legal because of dispensations or approvals granted by CASA and was certainly not prudent.
So, given that affected persons and organisations have the opportunity to review an ATSB report, I suspect that they are taking the opportunity to delay the publication by suggesting changes while they boiler-plate their back-sides for the inevitable kicking that is going to come their way.