"plant senescense" is the process of aging in plants. Chlorophyll degradation during leaf senescence reveals the carotenoids, and is the cause of autumn leaf color in deciduous trees.
The coloration started maybe 1 week before flowering.
The plant has an interesting history, as an "infant" it had serious issues developing chlorophyll.
As a result it was seriously stunted during early growth and reached its flowering stage several weeks late. It's normally developing siblings were harvested at 12 weeks but she was harvested at 16 weeks!
discussing this plant on reddit made me consider the fact that this plant's extreme coloring migh be caused by nitrogen problems. Your Theories on how this coloration happens are welcome and I'll be happy to answer any questions you might have about the plant.