It works for me, but it doesn’t give you swiftness instant but it ticks like 5 times i think.
So you should get swiftness on creation of the symbol and then after a second again and after one more second again …
Edit: Too slow, but:
I figure it was a pulse and your right it should do it faster. Also sometimes i can’t stop if being chase by a big zerg. :P
cast it in front of you, so you will always stand in when it’s on the ground,
only works if you’re going straight.