Thank you everyone! I am so excited that it worked out as well as it did and if not, then I will have certainly learned something.
This is what I know so far: The FO is the Fudge Brownie from Crafter's Choice. It did not accelerate from what I could tell and in fact, fell quite the opposite happened. I didn't have any vanilla stabilizer and so I only put the FO in the brown batter, and not the white. The white that is in the brown is turning and the brown is getting much darker (it is not as dark as in the picture, but rapidly getting there. The white that is on the top, so far, is super white.
When I poured the brown batter, it was very liquidly. So much so, that I was worried about using the white to achieve those tops because of the difference in consistency of the two colors, so I threw it in the freezer and waited about 15 minutes and then put the white on top and fluffed it. The white was considerably further along. I'd say a step past pudding, white the brown was just stable enough to have the white sit on top. I know now I should have just put the white on top gently and then textured after it firmed up a little. I say this because the smashed piece was thrown into a plastic baggie and jammed into my pocket so I could take it to let someone smell and by the time it rode around in the pocket all day, it was in piece, and I don't know if it was the difference in texture and the wait, the FO, or just a lucky smash, but the white was pulled almost perfectly from the brown bottoms. It is not separating on any of the bars and not separating in the center, so I am hoping an undisturbed cure will stop it in the bars, or that it was just a lucky break. We'll see what happens with it. I will be paying close attention since it was my first time using anything other than just oil. I suppose it could also be the cocoa vs. non cocoa?? I still think it was the wait and difference in texture and not anything I added. But I am super excited!!