Atol's not wearing off at the same time?

[Ashintar]

Cast:
[Mon Mar 03 13:36:16 2014] You begin casting Atol's Spectral Shackles.
[Mon Mar 03 13:36:19 2014] A frost giant savage's feet are shackled to the ground.
[Mon Mar 03 13:36:19 2014] A frost giant's feet are shackled to the ground.
[Mon Mar 03 13:36:19 2014] A frost giant savage's feet are shackled to the ground.
[Mon Mar 03 13:36:19 2014] A frost giant's feet are shackled to the ground.

Wore off (two had died):
[Mon Mar 03 13:38:51 2014] Your Atol's Spectral Shackles spell has worn off.
[Mon Mar 03 13:38:54 2014] Your Atol's Spectral Shackles spell has worn off.

not sure if it's a delay in the tick but these should wear off at the same time?