The Office for Standards in Education confirmed the inspector would be free to continue his work while an investigation into the incident takes place.
The disclosure comes two months after The TES revealed that Ofsted allows former heads of failing schools to be inspectors and sit in judgement on others.
Fearnside school, Hertfordshire, contacted Ofsted and contractors VT Education for reassurance when they learned they were to be visited by the same inspector.
Lynne Monck, headteacher, said: "I have been assured by VT Education that they have complete confidence in the inspector."
Ofsted was forced to admit that judgements on the leadership and management at Lordswood school, Birmingham, were "almost identical" to those given by the same inspector to Parkside school in Bradford.
A letter to the school said: "The number of errors and the duplication of the leadership and management section in the draft report are not acceptable."
Jane Hattatt, head of Lordswood, won the admission from Ofsted a year after her school was inspected and after threatening legal action.
Ofsted upheld six of her 31 objections and agreed to write an addendum to the school's report. But it refused to share the evidence on which judgements were made.
Mrs Hattatt said she planned to complain to the independent adjudicator about the time taken to tackle the complaint and to apply to see the evidence under the Freedom of Information Act, which comes into force next month.
A spokeswoman for Ofsted said sanctions against inspectors who were found to have copied work varied.
She said: "At the less serious end of the scale, in the past we have instructed an inspector not to duplicate writing formats from one report to another and have monitored his or her work to ensure that this has not been done.
"At the other extreme, in the most serious cases, we have moved to deregistration."