I'm going to be honest, I'm not 100% sure what is happening with this bug, but here are the repro steps:

1. Cast the purple magic spell Haste on self. (Specifically, I am using a Charge 5 Crystal, with 25 Purple Magic)
2. Move forward
3. Footstep sounds do not change in pace
4. Movement speed does not increase unless running (may be how the spell is supposed to work, I am not sure)
5. Log off
6. Log back in
7. Footstep sounds DO change in pace
8. Movement speed seems the same(?)
   

Like I said, not entirely sure what the actual behavior is supposed to be. But one thing or another isn't working quite right.

EDIT: After further testing, some more info:

1. Repro until step 4 above
2. Start running, movement speed increases
3. Movement speed seems to properly increase after you stop running

However this doesn't seem to be consistent. Sometimes this works, sometimes it doesn't.