England's exams watchdog, Ofqual, is to set out its initial findings on the row over English GCSEs.
Head teachers urged the exams regulator to investigate the changing of grade boundaries for exams this year.
Exams regulator Ofqual highlighted concerns that modular GCSEs created particular risks in maintaining standards because they allowed pupils to "bank" grades early.
The watchdog came up with a workable solution that might have avoided the row that has erupted since last week, but decided not to implement it, the TES said.
Headteachers have claimed that tens of thousands of teenagers could have been adversely affected by grade boundary changes in GCSE English.
The TES reported that former Ofqual chief regulator, Isabel Nisbet, raised the problem in October 2009 when modular GCSEs were first introduced.
She said that grading of individual modules could mean that when it came to the overall grade "the outcome is automatic", adding: "The machine goes ping and out pops the candidate's results. There is no discretion."
As a solution, she proposed banning pupils from "banking" grades from modules towards final results.
Marks from modules could stand, but the grades awarded would remain provisional until the overall mark for the qualification had been finalised.
Ms Nisbet, who left the regulator last year, did recognise downsides to her solution.
Pupils might feel cheated if provisional grades were changed and it might encourage "game-playing" among schools over when was a good time to cash in modules.
She also revealed that Ofqual had rejected an alternative strategy of allowing the modification or "hyper-correction" of a final module as an adjustment mechanism to the overall result.
Ofqual has admitted there are questions about how grade boundaries were set in a small number of English units over the year.
It said it was investigating the issue and was due to publish an initial report today.
GCSE pass rate fell for first time
- National GCSE results for all subjects in England, Wales and Northern Ireland revealed 69.4% of exams were given at least a C grade - down 0.4 percentage points on last summer.
- It is the first time the A*-C pass rate has fallen in the 24-year history of GCSEs.
- Angry headteachers claimed that exam boards had raised grade boundaries in English halfway through the year amid fears that too many children were going to get a C.