Is Kundalini Awakening Permanent?
When Kundalini awakens appropriately, it is permanent. That does not mean an awakening leads to spiritual enlightenment right away, or even in this lifetime. Kundalini can stop at any of the seven chakras and get stuck. When this happens, it is necessary to continue doing one's practice to progress.
Swami Lakshmanjoo, the great sage of Kashmir Shaivism, said in his book on the Shiva Sutras that Kundalini leads to the ultimate goal, enlightenment. Still, the practitioner may not get there in one lifetime.
Having one or two experiences with Kundalini does not make one enlightened. It could, of course, do that, but that is not the norm. To guide Shakti from chakra to chakra upwards to the crown takes dedication and continuous practice.