Some scholastics confessed it beyond reason in this life, notably Cardinal Cajetan
Some scholastics found this difficulty so hard that they frankly confessed their ignorance on this point. They judged it beyond the reach of the human mind so long as the mind is burdened with this mortal body.
One of them was Cardinal Cajetan, a very famous figure among the scholastics. Sharp and subtle as he was, he could never satisfy himself here. He held that the harmony of free choice with God's providence cannot be explained or understood in this life, as his commentary on the first part of Thomas, question 22, article 4, shows.
Latin
III. Haec difficultas tam ardua visa est Scholasticis nonnullis, ut hac in parte suam ignorantiam ingenue fassi sunt, & existimaverint rem esse quae superat mentis humanae captum, quamdiu mortali hoc corpore gravatur. Quo de numero fuit Cardinalis Cajetanus inter Scholasticos vir admodum celebris. Is enim, quantumvis acutus & subtilis, hac in re nunquam sibi potuit satisfacere, & putavit concordiam liberi arbitrii cum divina providentia, in hac vita esse inexplicabilem & non intelligibilem, ut videre est in ejus commentariis in primam partem Thomae, quaest. 22. art. 4.