Decay doing 0 damage (in General)

So me and piper were testing out decay but something weird has happened:
First I cast AMF:

Me cast Antimagic Field on Moon's Spawn (0.90)
Me cast Antimagic Field on Dragnipur (0.84)

In the battle logs, throughout the whole battle, his minion Dragnipur doesn't do any damage with decay. Only Moon's spawn does do damage.

What can be the cause of this?

Here is his battle log for the 1st round (last round of ranged) and 2nd rounds where he does damage (first round of melee).

Note: he has unequipped his ranged weapon and his familiar.

First Round:
Dragnipur takes damage from his own Decay (0)!
Dragnipur's Decay hit Guo Jia for no damage


Second round:
Moon's Spawn takes damage from his own Decay (1,751,659)!
Moon's Spawn's Decay hit Guo Jia [232,319]
Moon's Spawn takes damage from his own Decay (1,751,659)!
Moon's Spawn's Decay hit Guo Jia [232,319]
Deng Ai absorbs damage [232,319]
Dragnipur takes damage from his own Decay (0)!
Dragnipur's Decay hit Guo Jia for no damage

He is overburdened.

If you are over your ENC, you cast decay but it does 0 damage.

Directly from the Wiki under Direct Damage spells, subheading Decay:

Any encumbrance at all will reduce decay damage to 0.

Well that was quick. Thanks! :)

dang, I can't read. Guess I gotta do this to myself too after I made fun of titan. :(

http://www.youtube.com/watch?v=gGLxrFAhdoo&feature=related

It is a question that infrequently pops up in the forums.

Given the other DD spells just lose levels, decay is a strange spell in that it just goes limp if you are encumbered.