Not only is the practice legal, but it is happening with much greater frequency since Indiana hired a private operator — IGT Indiana (formerly GTECH) — to run nearly all of the operations of the Hoosier Lottery.
https://www.indystar.com/story/news/politics/2018/04/05/hoosier-lottery-often-pulls-plug-high-dollar-scratch-off-games-before-all-prizes-can-won/417720002/
