you may wish to recheck. there were 6 mill short positions held on 1st may.. which increased to 6.2 million on the 2nd may (not a huge increase) and 6.357,000 on the 3rd may.
1st may
http://asic.gov.au/Reports/Daily/2018/05/RR20180501-001-SSDailyAggShortPos.pdf
2nd May
http://asic.gov.au/Reports/Daily/2018/05/RR20180502-001-SSDailyAggShortPos.pdf
3rd may:
http://asic.gov.au/Reports/Daily/2018/05/RR20180503-001-SSDailyAggShortPos.pdf