Flowers on photos 2 has green stems but leaves in a similar shape on photo 3 has red stems. Does this plant goes red after flowering? Also some leaves in other parts are red and some are green.
It could be something like what happens is deciduous trees. When it is getting to the time for the leaves to fall, if I remember rightly, the chlorophyll breaks down and the goodies in the leaves are drawn back into the plant. At about the same time, substances that are not good for the tree are laid down in the leaves. These are often coloured.