@bizuktag As of today, I am also having this exact problem with the lower bunks. If the lower bunk is placed parallel to the top bunk (like a traditional bunk bed), it works fine. But if the lower bunk is placed perpendicular to the top bunk, the bottom bunk becomes unroutable.
I have also had problems with Sims not being able to use the top bunk if there is a dresser snapped to the bottom. It has made designing small bedrooms for kids very difficult since none of the space saving features the game is supposed to have are working correctly.
