User blog comment:Xilinoc/Ch. 613 - The Ordinary Peace/@comment-3219912-20150129154335/@comment-1268838-20150129222959

It's possible that it's a mistranslation. While it wouldn't surprise me in the least if Yasochika retired to pursue a career as a writer or something, we've already seen him doing 4th Division stuff in this arc.

The less likely possibility is that they share the seat.