Hodge was cleared of an offence after tackling Fijian flanker Peceli Yato by matchday officials during the Pool D encounter last Saturday at Sapporo after reference to the TV pictures.
But he was then cited for a high tackle on Sunday and banned for three games on Wednesday.
"The Player conceded that he had no effective knowledge of WR’s 'Decision making framework for high tackles'; had not been trained on it; was not across it because the tackles he makes are predominantly in the waist to knees area," the disciplinary panel's report said.
"To the Panel, this was of some general concern; and will be commented on later."
The report also revealed the extent of the injury to Yato, who Hodge caught in the head with a tackle in the 26th minute.
The best player on the field up to that point, Yato was forced to sit out the rest of the match, as well as Fiji's second game against Uruguay on Wednesday.
On his third examination, the flanker reported "increasing symptoms of headache, ‘pressure in head’, dizziness, blurred vision, sensitivity to light/noise, fatigue/low energy, and difficulty concentrating", the report said.
"These have subsequently all improved but largely all remain. He has been unable to complete any of the stages of the graduated return to play due to these symptoms."
Hodge, who will now miss Australia's crunch clash with Six Nations champions Wales on Sunday as well as the matches against Uruguay on October 5 and Georgia on October 11, can appeal the decision within 48 hours.
Rugby Australia have yet to comment on the punishment.
World Rugby have made much of their campaign to rid the game of high hits and the fact that the match officials did not penalise Hodge even after reference to the TV pictures will be an embarrassment for them.
Hodge's ban has been received with fury by the Australian media, with Sydney's Daily Telegraph describing it as "farcical" and other outlets suggesting Hodge was made an example of by World Rugby.
It is rare that Clive Woodward, who led England to their World Cup final victory over the Wallabies in Sydney in 2003, gets much good press in Australia but his criticism of the decision was widely shared.
"Totally wrong decision, will have huge implications for the tournament - for me this is a yellow card and no more," Woodward wrote on Twitter.
"Has any of those making this decision ever tried stopping someone as powerful as Yato by wrapping their arms around him? Good luck if you try that!"
Lee-Lo gets three match ban
Samoa centre Rey Lee-lo has been suspended for their next three matches at the Rugby World Cup for making a reckless high tackle in Tuesday's 34-9 victory over Russia, an independent judicial committee said on Thursday.
Both Lee-lo and hooker Motu Matu'u were given yellow cards by referee Romain Poite after the television match official reviewed their tackles on Russia captain Vasily Artemyev within two minutes of each other.
Tournament organisers confirmed the two were cited for acts of foul play and the committee deemed Lee-lo's tackle dangerous and worthy of a red card instead of a yellow.
"The committee... applied World Rugby's mandatory minimum mid-range entry point, which was introduced in 2017 to mitigate the risk of head injuries, carrying a minimum six-match suspension," the committee said in a statement.
"Having acknowledged Lee-lo's disciplinary record, good character and conduct at the hearing, the committee reduced the six-match entry point by three matches, resulting in a sanction of three matches."
Lee-lo will miss Samoa's pool games against Scotland, Japan and Ireland. The 32-year-old has 48 hours to appeal the decision.
Matu'u's hearing was also scheduled for Thursday but the committee is yet to issue a final ruling on his citation.