continued from above…
Theoteknos of Livias
It was fitting … that the most holy-body of Mary, God-bearing body, receptacle of God, divinised, incorruptible, illuminated by divine grace and full glory … should be entrusted to the earth for a little while and raised up to heaven in glory, with her soul pleasing to God (Homily on the Assumption [ca. A.D. 600]).
Modestus of Jerusalem
As the most glorious Mother of Christ, our Savior and God and the giver of life and immortality, has been endowed with life by him, she has received an eternal incorruptibility of the body together with him who has raised her up from the tomb and has taken her up to himself in a way known only to him (Encomium in dormitionnem Sanctissimae Dominae nostrae Deiparae semperque Virginis Mariae [ante A.D. 634]).
Germanus of Constantinople
You are she who, as it is written, appears in beauty, and your virginal body is all holy, all chaste, entirely the dwelling place of God, so that it is henceforth completely exempt from dissolution into dust. Though still human, it is changed into the heavenly life of incorruptibility, truly living and glorious, undamaged and sharing in perfect life (Sermon I [A.D. 683]).
It was fitting that the she, who had kept her virginity intact in childbirth, should keep her own body free from all corruption even after death. It was fitting that she, who had carried the Creator as a child at her breast, should dwell in the divine tabernacles. It was fitting that the spouse, whom the Father had taken to himself, should live in the divine mansions. It was fitting that she, who had seen her Son upon the cross and who had thereby received into her heart the sword of sorrow which she had escaped when giving birth to him, should look upon him as he sits with the Father, It was fitting that God’s Mother should possess what belongs to her Son, and that she should be honored by every creature as the Mother and as the handmaid of God (Dormition of Mary [A.D. 697])
Venerable to us, O Lord, is the festivity of this day on which the holy Mother of God suffered temporal death, but still could not be kept down by the bonds of death, who has begotten Thy Son our Lord incarnate from herself (Gregorian Sacramentary, Veneranda [ante A.D. 795]
Given the above evidence, it surely points to the fact that the church has always held constant on this teaching.