When I look at the whole plant and at this bud I can only say good job she is almost ready for harvest.
This is 100% natural, cannabis is a one season plant so after producing the buds she will fade colours and start dying.
Not every bud is ripening at exactly the same moment. Soon all the buds will show you these signs.
Look at the trichomes. When 70% is cloudy and 10% amber she is at full potency and ready for harvest.
Again not every bud is ripening at the same speed. So you can choose to harvest parts of the plant each time.
Or and this got my preference, harvest everything in 1 time when the largest part of the plant is at full potency. This way you get a different high from different parts from the same plant.
Happy Harvest!