I'm playing arena on Android. Whenever I try to use Untimely Malfunction to change the target of a counter spell to Untimely Malfunction, the game locks me out of options. It doesn't let me select a new target. It doesn't let me do anything other than concede or timeout. I can't back out of it, either. Redirects have been used to counter counter spells for years, but I don't think the arena program knows how to handle it.