Room with crystal ball container

Toward the end of the game, there is a room where you need to put a container in your inventory. After I go to all the other rooms in that journey, I come back and put the container (which resembles a dismantled crystal ball) back on the altar. The door then opens so I can get the slingshot to continue to the next room. I did this once or twice. But the last few times I played, the crystal ball wouldn't stay on the altar - it kept falling back into inventory. What am I doing wrong? Or has the game developed a glitch?

I cant get pass 60, if you are that far you must have made it. can you help me