No Chest in Dungeon

I have no clue if this is a more often thing than not, but while exploring on my world I found a dungeon with not chest just a ominous small room of cobblestone.

https://preview.redd.it/uhhae36aepsf1.png?width=1920&format=png&auto=webp&s=d9581694690090df079195bcc520cd478b885a42