The maze does not stay the same shape. That is the thing nobody writes down because it sounds like a story and because it is very hard to prove from inside.

MalfoidI walked it every summer from six to fourteen. I know it. There are nine turnings and a fountain in the middle and the fountain has been dry since 1977.

CorvinaThen walk it tomorrow and count. I have counted four times in nine years and got four different numbers.

The covenant says maintained. It does not say the same shape. A boundary only has to be a boundary, and a boundary can move as long as it closes.