The Verses
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Peace,
What specifically are you referring to?
As far as I know the only mixed surah is number 9 where the last two verses are labeled meccan while the surah is medinan if I recall correctly, which was one evidence used to rashad khalifa in his research to prove that they were false additions to the Quran, they have an article on submission.org on them.
In all honesty as far as I can ascertain we have no way of actually verifying what surahs were revealed where, As the order and place of revelation is based on hadiths, except what the Quran itself actually provides as clues to the whereabouts and activities of the people and events it refers to.
As always it pays to verify things ourselves as much as practical and not follow after that which we have no knowledge of as the Quran recommend