Chest help

[severe crater]

Hi!
So I’m just going around the castle finding things I’ve missed, and the map in the corner of the screen is telling me there’s a chest here, but I can’t find any way to get to any sort of hidden room to grab it? It’s right outside professor binns’ office behind the history of magic class. There’s no other room there, it’s just hallways and walls. Is this a glitch or is there actually a way to get to it? As you can see, the mini map says I’m facing the chests location but I can’t figure anything out to get to it

[modern copper]

There’s a tiny arrow above the chest, meaning it’s higher up than your current place on the map

[severe crater]

I never noticed that it’s so small!! Thank you so much ☺️💜

[wide light]

There's chests around the game with eyes on them how do I open them?? New player here.

[modern copper]

Use the Disilusionment charm when out of their sight and walk up to them, you can only open them when invisible