I would have thought that circular relationships in MB could not occur as they could cause big problems. But it would seem that they can be constructed (at least in a semantic sense).
For example this work. It can be seen that the work is described as having this arrangement but is also shown as a medley of of that same arrangement!
This seems to be a semantic nonsense*, and I am concerned that it seems to be permissible to enter such relationships.
On closer inspection, it appears that both the arrangement and the medley are ’ direction: “forward” ', which might explain why MB doesn’t consider the relationships to be circular. However, that begs the question as to why “medley of” is considered to be a ‘forward’ relationship, whereas “part of” is considered to be ‘backward’. Can anyone explain?
*It is actually a double nonsense, since how can you have a medley of just one work, let alone that work being an arrangement of the same said medley?