Stampede (gap closer, morph of Critical Charge) can often fail in a way that leaves the player unable to do anything but move. No casting skills, no bar swapping, even dodge roll doesn't work. This lasts for several seconds or until death. Usually the latter, since the bug makes you defenseless after gap closing. One case where this seems to happen is if a nighblade stealths when you are casting it, though it happens in other occasions as well. This is a frequent occurance in Cyrodiil, while I haven't seen it happen anywhere else.

A comment I saw about this bug somewhere said that the disabling of all your skills and moves lasts until the damage number from the skill appears. Perhaps in some cases when the skill fails to do damage at all, the disabling is never removed? This behavior seems unique to this skill, at least I haven't encountered it with other gap closers.

The bug might also affect the base skill and the other morph, but I don't have personal experience of that.

edit:

It happened again, I'm fairly certain that the reason for all of this is location desync caused by the gap closer, since when it happens enemies will also be able to fire projectiles at you, even though they don't have line of sight as far as the player client can tell

edit 2:

I'm getting the bug with almost every cast of Stampede in a laggy keep fight. Can also confirm it is location desync, this time I lived long enough to run far away, when I died, dead body was where the desync happened, instead of where I ran to. In other news, I stop using this skill in Cyrodiil, it is more likely to kill the user than harm the target. Also it doesn't require any special circumstance, using it on stationary target from fairly close can also cause the desync.