"-[PFObject <FIELD NAME>]: unrecognized selector sent to instance" when accessing field of related object #3

@interface Foo : ParseModel
@property(nonatomic, strong) Bar *bar;
@end

@interface Bar : ParseModel
@property(nonatomic, strong) NSNumber *theAnswer;
@end

        PFQuery *query = [PFQuery queryWithClassName:@"Foo"];
        query.cachePolicy = kPFCachePolicyCacheThenNetwork;
        [query includeKey:@"bar"];
        [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
            // Print information about foos.
            Foo *foo = objects[0];
            expect(foo.bar).to.beInstanceOf([Bar class]); // FAILS: expected Bar but was actually PFObject
            expect(foo.bar.theAnswer).to.equal(@42); // -[PFObject theAnswer]: unrecognized selector sent to instance...
        }];