Those are ready-made excuses.. The thing is, he was KOd. As simple as that. His chin, at best, is above-average, and I may add, he can regroup very well after a KD. He has shown that before.
Yep, that was when his chin was suspect. Though I think in the Yeshmangbetov fight he got KD'd more out of over confidence and a lack of defensive polish than anything else.