Caused by a change in FactoryBot 5. Associations in factories are now
constructed using the same strategy as the base object, meaning that
using `build` to construct an object will also construct the
associations using `build`. This meant that overriding `create` to do
`build` + `save` broke the way that associations were constructed.
https://github.com/thoughtbot/factory_bot/blob/master/GETTING_STARTED.md#associations