NaN/translation errors with configurable joints and animation after upgrade to Unity 5

So I upgraded unity and my games project. I've cleared all of the code based errors it presented.

Every single animation which has a model containing configurable Joints is receiving errors :

Transform position assign invalid...(NaN, NaN, value) where value is the free rotational value of the config joint. Thus if x and y were locked, it generates the errors for them.

 transform.position assign attempt for 'LEFT_FOREARM' is not valid. Input position is { NaN, NaN, 22342344711864320.000000 }.

I think it's related to the animations though, as I do not generate any errors for config joints outside of mecanim animations. I found this, http://docs.unity3d.com/Manual/UpgradeGuide5-Animation.html, and don't know A: if it applies to me. B: Where those animation scripts might be or how to access them. C: If I'm barking up the wrong tree thinking it's the animations rather than the joints themselves.