User blog comment:Xilinoc/Ch. 553 - Frozen Cross/@comment-2243814-20131018222036/@comment-11051098-20131018232259

Maybe all that happens is that when the Bankai gets hollowfied, the Sternritter's body instantly rejects the Bankai to avoid injuries caused by the hollowfication.

Or it could be that the Sternritter is weakened by the short contact with the hollowfied Bankai, enough to become easier to defeat. But I hope Cang Du isn't too much weakened or whatever happened, and can still fight, even if he eventually gets killed. If he does now, it'll be too short and boring.