In the structure minecraft:ancient_city/structures/ice_box_1, it looks like the trapdoor is supposed to be closed by default, so that the pressure plate actually does something. But the lever that opens the pressure plate is already turned on.
Example ice box in seed 1 at /tp @s 2932 -47 6971
I think they made this change intentional, so the Noteblocks trigger a Shrieker nearby, and doesn’t actually have to do with a puzzle.