It seems that when kirikaeshi is taught, especially when done slowly with emphasis on the correctness of the movement, the footwork is supposed to resemble nidan datotsu where the cut is made as the left foot is pulled forward when going forward, and as right foot is pulled backward when going backward. Kendo Shidou Yoru (official instruction manual by ZNKR) only mentions that the ashisabaki should not be an ayumi ashi with no specifics about when the cut is made, but a search on the correct footwork during kirikaeshi seems to result in what I have just mentioned.
Here is a video where Shiraishi sensei (Hanshi, 8 dan) of Marugame Budokan Isshin-kai demonstrates correct form during kirikaeshi, both slow and fast.
A near-replica of Kendo Shidou Yoru on kirikaeshi (in Japanese)
Kenshi 24/7 article on Kirikaeshi (no mention of footwork in detail, but listed here as an instructional reference)