When I was Episcopalian, I was very "high". I did and do believe in Transubstantiation, and so did our rector.
But the XXXIX was part of the English turmoil of the 16th c. (which is why it was relegated back in the 70s to the status of "historical documents", at the same time the communion service was revised to track the Roman Rite more closely - input of the "high" wing)
Ahem...it was relegated back in the '70's to the status of "historical documents" by the same folks who gave us: female priests & bishops, a watered-down & unscriptural Book of Common Prayer, the practice of Mysticism (including, but not limited to: Druidry, walking the labyrinth, Taize music, Women's "Eucharists" & Buddhist prayer beads on which they've hung a cross & remarketed as "Episcopal" prayer beads). Shall I go on? Let see...abortion, co-habitation, out-of-wedlock pregnancy, unlimited divorce & remarriage, non-celibate homosexual clergy, and same-sex "marriages." All these things are A-OK in the "new & improved Episcopal Church" - thanks to these enlightened, progressive thinkers who decided 30 years ago that the 39 Articles of Religion should be relegated to the status of historical footnotes. Bah!