According to PVP Live, since the custom game was introduced, Mei’s ult began to vanish after death, and after the Uprising update, her beam and ult no longer slow enemies down. In a status update to a Reddit post revealing the problem, Bill Warnecke with Blizzard said, a fix for the disappearing ult is now available in a live patch. However, Mei players still cannot slow down enemies when using her ult. Do you have anything to share on this?
The Reddit post is here: https://goo.gl/dG6Rdn