I have a chimera (Kilauea) that is apparently sporting on me at the moment. What I've learned from others so far is that they need very good culture. Temps around 70 degrees F, and to have the proper amount of water. I know mine got too cold this winter as it was unusually cold here, and I just converted to wick watering so they may have gone through some wet-dry cycles they didn't like. I'm not going to let it discourage me though. Maybe some others have some more info for you.

Any plant sports if stressed. They do better with a consistent care. In my opinion it is important to keep an eye on suckers and root them for perpetuation of the chimera. The old plant eventually gets tired...

Sometimes if the chimera is sporting - you can try to cut the sporting top off and leave bottom leaves on a stem which hopefully produce the correct suckers.

Irina