Then there are these guys that Peter tells us about:
2Pe 2:20 For if after they have escaped the pollutions of the world through the knowledge of the Lord and Saviour Jesus Christ, they are again entangled therein, and overcome, the latter end is worse with them than the beginning.
2Pe 2:21 For it had been better for them not to have known the way of righteousness, than, after they have known it, to turn from the holy commandment delivered unto them.
2Pe 2:22 But it is happened unto them according to the true proverb, The dog is turned to his own vomit again; and the sow that was washed to her wallowing in the mire.
These people had "escaped the pollutions of the world through the knowledge of the Lord and Saviour Jesus Christ". In other words, they were born-again Christians. But they were "again entangled therein, and overcome", and "the latter end is worse with them than the beginning." Life happens. Temptations happen. And, yes...born-again Christians can become "entangled therein and overcome."
Yes, even today, it happens.
But God, through the mouth of His Apostle Peter, tells us that "it had been better for them not to have known the way of righteousness, than, after they have known it, to turn from the holy commandment delivered unto them."
It's no use trying to say that these people did not have "heart-faith". None of us can see into someone else's heart...this is not a judgment we are called to make. The passage doesn't say that they didn't have heart-faith, it says that they had escaped the pollutions of this world, and that they had known the way of righteousness. It's no good to try to say that they had no root in them. That's just trying to twist the passage to make it fit into the OSAS doctrine. It doesn't help to try to say that God wasn't really saving that one anyway...God has not called any one of us to sit in committee with Him and decide who is and who is not to be saved. The gift of salvation is freely offered to every single one of us.
"But it is happened unto them according to the true proverb, The dog is turned to his own vomit again; and the sow that was washed to her wallowing in the mire."
And that is what God has to say about it.