When migrating a quiz from classic to new any question-level feedback for answering the question correctly is migrated as correct answer feedback overriding any existing answer-level feedback for that answer option and creating answer-level feedback if none exists. This does not happen with question/answer-level feedback for incorrect answers.

In this example I included feedback at both the answer and question level on the classic quiz, but after migration the answer-level feedback for the correct answer option was overwritten by the question-level feedback for answering the question correctly.

In this example there was no answer-level feedback for the correct answer but there was question-level feedback for the correct answer. After migration the question-level feedback was put in at the answer-level.