Reading between the lines, it seems that the "simulator issues" are more than likely relating to the company's rush to get as many people as possible endorsed on the Metro before the provisions of CAO 40.1.0p2B come into force in April.
At the moment, they do their Metro endorsements in the actual aircraft: a single flight after two days of groundschool, unlike the other two Metro operators on the same aerodrome, who both have long groundschools and a week in the Ansett simulator.
Is that enough to suspend RPT operations? I wouldn't have guessed so, so there is clearly far more at play behind the scenes.
And I am still confused by the finger-pointing. Either CASA or JH grounded the fleet, that's for sure. Perhaps the FAF (Friday Afternoon Fax) from CASA was ambiguous and JH interpreted it as a grounding, while CASA did not intend for such to happen. Perhaps JH acted to err on the side of caution, but that certainly does not seem to be the tone he is taking with the media over the weekend.
Or perhaps CASA worded it in such a way as to imply a grounding, but left themselves an "out" to say it wasn't mandatory. Why, though, is beyond me.