Possible Decay Bug (in General)

I fought Solid Snake's character, Solid Snake and noticed I was doing 0 damage with decay.

Solid Snake cast Antimagic Field on Ranthor (0.11)
Solid Snake cast Antimagic Field on Bariagan (0.00)
...

Ranthor takes damage from his own Decay (0)!
Ranthor's Decay hit Solid Snake for no damage
Bariagan takes damage from his own Cone of Cold (0)!
Bariagan's Cone of Cold hit Solid Snake [596367]

Ranthor takes damage from his own Decay (0)!
Ranthor's Decay hit Solid Snake for no damage
Bariagan takes damage from his own Cone of Cold (0)!
Bariagan's Cone of Cold hit Solid Snake [953016]

Any idea why this is happening?

decay minions encumbered?

enc seems to completely ruin Decay...

For Ranthor:
Encumbered at: 14,284,434
Equipped NW: 14,265,297

So 0 encumbrance normally.

Encumbrance 0.10 after he casts ethereal chains. Would that do it?

any encumbrance at all makes decay not work