Ms Trad has previously admitted to meeting personally with both Ms Cook and Ms Ferdinands during the recruitment period but always denied interfering in the process.
A senior Education Department executivewas stood aside just days after Ms Trad resigned her frontbench roles in relation to the matter.
Last month,Crime and Corruption Commission chairman Alan MacSporran said the investigation into Ms Trad waslaunched one month after it was referred to him in November,though the CCC did not inform her until May.
In a statement released with the report on Thursday,Mr MacSporran said the investigation uncovered"worrying and disappointing"practices that should concern all Queenslanders and public sector employees.
These included poor record keeping — or no records at all — of key decisions from department officers and some selection panel members.
"We recovered an email that was the subject of an instruction to delete a public record,a recruitment process was interfered with by people not on the selection panel,a candidate was misled by department officers and false information was published or used to make decisions,"he said.
Other department officers either thought it was a good idea or were aware of the idea to"test"a candidate during a meeting with Ms Trad — though not instigated by her — despite the selection panel having already made a decision.
Mr MacSporran said that meeting was,in the watchdog's view,"entirely inappropriate".
"All Queensland public servants and elected officials should read this report to see how a straight-forward recruitment process went off the rails,"he said.
"This type of conduct should never occur again."
The CCC report concluded that while Ms Trad did not intend to influence the principal position,the manner in which the department,and specifically its deputy director-general,approached the situation"meant it had that result".
It recommended mandatory induction and awareness training for ministers,their key advisers,directors-general and their deputies"to ensure all parties are clear on expectations,responsibilities and accountabilities in effective and ethical public service system leadership".
The watchdog also recommended reforming job security of department bosses and separating their roles from the"influence of ministers".
A confidential report and relevant evidence has also been forwarded to the Public Service Commission chief executive for consideration of any disciplinary action against those identified.
Mr MacSporran was expected to address the media on Thursday afternoon.