@Zach:
This may sound ridiculous, but maybe they're removing it so they can save it to put in a "Volume 0" or for Strong World promotions in Jump if and when Strong World appears in the U.S.
That would be great, but considering it seems like there hasn't been so much as a whisper from Viz on any indication of licensing Strong World or any of the other OP movies for that matter…and plus also considering Viz's tendency to remove cover pages of random chapters it doesn't look too good.
On another note, I am shocked that neither of the color pages were published in this month's Jump, I mean maybe not including one I could understand, but choosing to omit both of them a bit of a shame. One can only hope that Viz will publish the other Color Walks some point in the future, but just like the movies, there has been nothing released in that regard either...