When in multicellular stage the cells placed in the editor in a specific place are instead put randomly when actually playing the game, end when reentering the editor to modify the creature the cells are in different and more disvantageous places then originally paced.
As this is only in the prototypes, it is not any priority for me to fix it. Before we officially finish the microbe stage and move on, anyone is free to come along and submit a fix to us as Thrive is open source.