When dying while in the ancestral city, objects tend to disappear instantly

As I said, when dying in the Ancestral City, the objects tend to disappear instantly for no apparent reason and without waiting for 5 minutes, it has already happened to me several times and I have lost valuable objects. Is it normal that being in hard difficulty being in an Ancient city? The first was because I fell from a great height, the second was due to the Warden's laser beam, I have never died near lava or fire or Creeper explosions, only by zombies, skeletons and enderman. Is it also normal for monsters to appear in the Ancient City?