It's more correct to say that flying with another instructor (who confuses the student) can be a problem.

Flying with =an= instructor who confuses the student is a problem, irrespective of whether it is the original instructor or a different one. The implication I picked up was that being exposed to a different approach is inherently confusing; it is that with which I disagree. Otherwise what you (and others) have said applies equally to the original instructor as to the substitute one.

Jose
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You can choose whom to befriend, but you cannot choose whom to love.
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