I am playing the Lost to the Ages quest on Xbox 360 and am at the part where I need to shoot the tonal locks in order to open them. I know the correct order, and I looked it up to double check that I had it right, but when I try to shoot the locks in that order it tells me I'm wrong and triggers the enemies to spawn. Is this a bug?

The order I am trying to do is Bottom Left, Bottom Right, Top Left, Top Right , Middle.

It lets me shoot the bottom left, but when I go to shoot the bottom right it triggers enemies.

It also lets me do bottom left and then top left, but then any one I shoot after that triggers enemies as well.

This glitch can occur, but it's easy to correct.

From the wiki:

Even just leaving the dungeon, reloading, and entering again can work.