As an assassin I have massive problems with this. Most often in pvp, but also in pve. Things like vanish, sprint, interupts, pretty much do nothing when I press them sometimes.
Im not sure, but I get the feeling its because of the animations my character is doing at the time stopping the ability animation being played. This is usually defensive animations, of deflecting attacks with my lightsaber.
This issue is not exactly the ability delay issue. Instead this can cause abilities to not do anything at all, for a good 10-15secs sometimes.