Consider this game state: [![GameState][1]][1]
d5 captures c6
Quiescence search returns about 8.0 as evaluation because after dxc6 and bxc6 Qxd6 would be played (then Qxd6 by black). A normal player would not play this move but quiescence search includes it in the evaluation and it would result in this end state:[![GameState after quiescence search end][2]][2] which would result in a huge advantage for black.
Is my interpretation of quiescence search wrong? [1]: https://i.sstatic.net/wfOrF.png [2]: https://i.sstatic.net/ACI6V.png