We've been running 3.5 in production for a while, and a few weeks ago we upgraded to 3.7. It seemed to run fine. This morning, one of my developers informed me of a problem he was having.
Specifically, we can no longer add fields from related content types. This is how I go about this:
1. Create the view
2. Add a filter to the view to restrict to a particular content type (=Departments)
3. Add a relationship based on an entity type field included in the Employees content type (e.g. Employees)
4. Try to add a field from the related entity type (Employees) to the view.
What you'll find is that none of the related fields show up. I confirmed that this behavior exists in 3.6, 3.7, and 3.7-dev.
Upon reverting to 3.5, the fields in the related content type are available to be added to the view.