Don't play DK so can't say for sure but probably same thing going on that is going on for stampede and other charges. I have a couple of 2hander builds and have found it is much twitchier in that if there is a small rock, large blade of grass, anything that might change elevation or line of sight it will get blocked. Sad but seems just need to work around it because it has been going on all year.
Every charge, leap and chain (so not the Sorcerer streak ability) are bugged, sometimes they won't work and their skill on action bars are greyed out and this it's been like that for a long time now.