After getting "a number of reports" that the day-one DLC for Ultimate Marvel vs. Capcom 3 was missing from the PlayStation Vita store, Capcom did a little looking and, yes, it ain't there because of "last-minute issues".
The problem is with making sure that a PS Vita and a PS3 with the same game and the same content play together nicely. Apparently, they don't with this pack, which includes Costume Pack 1 and the Jill Valentine and Shuma-Gorath characters.
"Everything has been addressed and Jill, Shuma and Costume Pack 1 will be available on the PlayStation Vita storefront next week Tuesday [February 28] during the regularly scheduled PSN weekly update," Capcom says.
Ultimate Marvel vs. Capcom 3 (PS Vita) - DLC Update [Capcom-Unity]