Not sure whether I trust Cohen or not. However his passport is not proof. I flew to Budapest and came home from Prague and the only two stamps in my passport were France and Amsterdam, the two airports I connected through.
if you flew in or out of the USA, US Customs has records of both.
https://www.cbp.gov/site-policy-notices/foia/records
A US passport is stamped upon entry into the Schengen zone and upon exit from the Schengen zone.
You entered the Schengen zone in France and exited in Amsterdam (or vice-versa), so you only got two stamps.
However, Michael Cohen can easily show that his passport doesn’t show entry and exit from the Schengen zone in the time in question - a trivial exercise.