As a non-native speaker of English, not only have I never heard this sentence before, but also I don't understand what it's saying. And yes, it looks quite grammatically wrong to me.

In any case, I view "my baby" here not as a direct object, but as a subject complement. The verb "is" is not an action verb but a stative one. It identifies the subject with a quality or characteristic, but it doesn't impose an action on a primary recipient as action verbs do on their direct objects.