Many books on QM state this so called von Naumann projection postulate i.e. that after the measurement system is in eigenstate of operator whose eigenvalue is measured. But in Landau Quantum Mechanics in chapter 7, author explicitly says that after the measurement system is in a state that coresponds to measured value but that these state are not eigenstate of any operator. Because of this author concludes that measurement in QM cannot be reproduced. (the only exception is measurement of coordinate) So this two statements (neumann and landau) seem contradictory to me, and that simple experiment would give answer which statement is wrong. So are QM measurements reproducible?