Yogic Samadhi vanished because it was not the highest insight. The Gnani, however never loses his Gnana.+

Bhagavan Buddha gave up his austerities of yoga as impossible and useless. [Page.70/71 "Buddhism in Translation” by Warren] 

Bhagavan Buddha got enlightenment only after he gave up Yoga. Unless one exercises his reason--there is no chance of getting the truth.

Where people cannot and do not think, they follow others. A Gnani will see the world and get to know it is only an illusory appearance. He is not blind; he sees three states or objects as it is, but he knows it is only a falsehood. Just as you see a mirage, the Gnani sees the mirage of this universe too; but he is not deceived by it. 

So long as one is ignorant, he will have the idea that God has created this world because the causal notion will be there. Nobody wants to suffer, and while the notion that suffering can be got rid of by appealing to God, these wishes will sway the mind to believe in God. For them,  religion will arise, but for the man who wants the truth, religion offers no consolation.

One has to inquire into the mind (the world) and its nature i.e. matter, there can be no such thing as  Advaitic wisdom or Gnana without understanding what is mind (universe). Seeker of truth will not be able to find answers in the path of religion and yoga are based on blind belief or imagination because they think the mind is within the body.  

The yogi or Gurus may just by saying “I know” and not explain how he knows the ultimate truth or Brahman. Because he has read it in the book or scriptures or his Guru may have told him “yogic Samadhi is liberation.

The Self-deluded believers tell others the same because he has not investigated if it is right. People give lectures and write books on yoga and eastern philosophy. 

Some may say for many years they are enjoying mystic exaltation, trances, meditations, and peace but they have verified what they experienced is really the truth. Then this state is not permanent because when this state passes away again they enter into duality. This state which is impermanent is not Gnana or Self—awareness.  This proves he had attained a yogic condition, but not Gnana. 

Yogic Samadhi vanished because it was not the highest insight. The Gnani, however never loses his Gnana. Dislodging a Gnani from his insight is an impossibility. Once he has thoroughly seen the truth he simply can't fall away from it. 

Remember:~

Many enjoy a similar sort of mystic exaltation and peace, but whether it passes away soon or endures the whole of life, it is not Gnana, because it did not come through striving to investigate the nature of the mind or world, it came only through meditation on the self; that is the yogic reward for such meditation but it is only one half. 

The Gnani not only gets inner peace but also truth because he also has grasped the truth about the matter, which is as much the Soul, the Self, which is present in the form of consciousness. 

It is not possible to stop the thought for more than a half-second whilst in the waking experience. If one succeeds in controlling thought and then banishes it, one passes into yogic Nirvikalpa Samadhi, which is identical to deep sleep. 

The only difference between ordinary deep sleep and Samadhi, therefore, is that the ordinary man falls asleep involuntarily whereas the yogi has the satisfaction of knowing that he has passed into sleep by his own effort of will in banishing thoughts. Thoughtless states are not wisdom because thoughts arise from the false self within the false experience. 

 There is no use in struggling to stop the thoughts which belong to the falsehood? One has to trace the source of the falsehood which is not the form of mind or universe to unfold the reality of the true existence. Thoughtlessness is not wisdom and thoughtlessness is not Gnanic or Brahmic truth.  :~Santthosh Kumaar