I think this distortion started sometime before the second council of Nicea, but it did not reach official ‘Mary as goddess’ until the mid-1990’s.
Is making up history a regular pastime of yours, or do you just dabble in it on occasion?
Cogitate on this for awhile: the earliest known prayer to Mary that is physically extant today is the prayer "Sub tuum praesidium," which exists on an Egyptian papyrus from the third century. That's before Christianity was legalized under Constantine.
St. Ephrem of Syria wrote in the "Nisibene Hymns": "Certainly You alone and your mother are from every aspect completely beautiful for there is no blemish in Thee, my Lord, and no stain in Thy mother". That dates from the 4th century.
There are many, many, many other examples.