Cragcroftshire treasure vault bug?

[𝐋𝐢𝐬𝐚]

There's this treasure vault in Cragcroftshire, where the icon of the vault keeps popping up on my map but I've already taken the treasure inside.
Anyone else with this problem?

Also, there's always these 5 rocks flying around in circles in that cave which indicate a blue light when doing revelio, indicating i'm supposed to do something with it?

[dEd_LoOnAcY]

Just shoot all the flying rocks down then the chest will pop up