Aflatoxwhat?!?!?

[WexMajor]

Arena silver. Opponent plays grey nymph, i play retrovirus to lure the afla, he does and puts another nymph down. I play 2 fallen druids and plague them.
No cell spawns.
He plays afla on both druids. I put down a brimstone eater and a photon and I improve them. Brimstone eater becomes a mutant malignant cell with immaterial. (no malignant cell are supposed to pop up from mutation or improve), photon becomes a 7/4 fallen elf with burrow.
Next he plagues me, giving ONE point of afla even to the healthy elf  (the mutant)
http://imageshack.us/photo/my-images/692/zaz9.jpg/ I haven't understood how to put images in post, so here's a link to what happened.
So, I have one question: what happened?

[serprex]

I've repeated this with Virus against AI1. I cast Afla on the Virus, infected a random creature, played a Virus to the same slot, and cast improve on it. At first it was a GotP with some skill, but then it remutated into a Malignant Cell with 1 other cost Destroy. Didn't get to use ability, TStorm killed, and playing a Virus to the slot and improving didn't repeat the bug

My guess is that statuses are tied to slots, and the aflatoxin slot triggers the slot to be filled with a Malignant but the mutant status also remains

Random test: mutating something with alfatoxin counters does not trigger a malignant cell mutant
Another random test: Malignant Cells on field. Aflatoxin on Virus, followed by Virus sacrificing, then wait. Malignant Cells reproduce over the slot, and the malignant spawn effect occurs twice on that slot

[WexMajor]

Fine for the first bug. What about the second one?