Video report by ITV News Correspondent John Ray
The Equality Act Review concluded the teacher assessment system - in place of cancelled exams - could negatively impact black, Asian and minority ethnic (BAME) pupils and those from more disadvantaged backgrounds.
The report authors say predicted grades risk possible "bias by teachers" and do not consider the "material disadvantages" of pupils from poorer backgrounds.
It found nearly 80% of students and parents who responded said they were worried about the predicted grades system.
Report authors say that equates to approximately 4.28 million students concerned about the predicted grades system.
Respondents raised concerns about bias in the classroom in relation to BAME identity, Islamophobia, favouritism, bad behaviour and social class.
The findings prompted report author Dr Suriyah Bi to warn the system could "structurally limit equality of and access to opportunities" for some students.
"BAME students are at greater risk than ever before to be plunged into futures that will be shaped by grade under-predictions," she said.
Indeed the report shows a fifth of BAME pupils worried about their predicted grades identified classroom bias - due to them not being white - as their biggest concern.
Speaking to ITV News Dr Bi, said one of the reasons respondents felt they could be discriminated against was due to a lack of anonymity in grading.
While exam papers are usually anonymous, pupils said they now feared being identifiable - and discriminated against - based on their names.
Dr Bi added that the grade prediction system failed to accommodate for "mitigating circumstances".
What were the concerns raised in the survey?
The report identified socioeconomic concerns as a significant concern in the predictive grades system too.
Of those surveyed, 19% said their schools were predicting grades using past exam performance at the school.
The report warned this is "unfair to students from schools in less advantaged areas" as well as those from poorer backgrounds.
It's something Darren Gelder, Principal at Grace Academy in Solihull, said could penalise current students through no fault of their own.
Mr Gelder said the school has worked hard to take into consideration each pupil's background as context in teacher assessments - but they await to see how this will translate to the final grade awarded to pupils.
He added that the grades pupils come away with "have to be right" as they have "a major impact on future life chances".
Mr Gelder told ITV News the school works "incredibly hard" to treat each pupil with a holistic approach - considering factors both in and outside of the classroom.
Concerns about predicted grades pre-date the pandemic, in 2016 a University College London study found most A-level predictions by teachers were over predicted in the majority of cases.
It found only 16% of grades were accurately predicted.
University graduate Kia Commodore says her "life would be completely different" had her grades been based on predicted - rather than the exams she sat.
The French and business graduate had been predicted to fail her GCSEs but achieved A and B grades across the board.
Ms Commodore says "the majority" of her school friends whose grades were under predicted compared to what they went on to achieve were "black or an ethnic minority".
Research carried out in 2011 by the Department for Business, Innovation and Skills found just 39 per cent of black students had their grades predicted accurately.
This was in contrast to 53 per cent of their white counterparts having their grades accurately predicted.