Hogwarts Valley Castle Puzzle

[Falaris]

Between Brockbury and Keenbridge there's an ancient magic location in a pretty grand castle.

On its ground floor facing the lake is 10+4 arches marked with yellow stars at various heights, and a sphinx which I believe signifies this is a magical riddle.

It's an interesting area with a few vaults and such, but.. nothing that seems to have anything to do with the mysterious details of the castle itself. Anyone else that has checked this?

Screenshot of part of what I think is the puzzle:

https://steamcommunity.com/sharedfiles/filedetails/?id=2940062804

Anyone else had a look at this?