Wijgrid will not work with breeze and angular. To save me repeating myself, please have a look at this post:
http://wijmo.com/topic/wijgrid-will-not-play-with-angular-and-breeze-together/
Your model, like most models, has circular references. We are not wijgrid experts (at all!) but we suspect that the wijgrid component - at least as you have it configured - is unprepared for objects with circular references.
Objects with circular references are not bad. In fact they are normal and expected in entity models. A customer has orders and each order has a property that returns its parent customer. If you don't
We suggest you consult the vendor on this topic.
If you are using the grid read-only, you can write a simple function to copy just the data you want to display from the queried entities into special purpose "ItemViewModel" objects; then load those into the grid. It's even easier to query with a Breeze projection because that returns raw data, not entities; just remember that Breeze isn't caching those non-entity results either.
The situation is more complicated if you want to edit the grid.
I want to reiterate that this is not a Breeze problem. It is a problem with the grid control.