Medieval Christians attributed to Shi’ah a Gabriel-error theology most Shi’ah rejected

Evidence

William and those who followed him quoted the idea that ‘Ali had been intended by God to receive the message which Gabriel by error gave to Muhammad; this is an extreme view which most Shi’ah of Ja’fari confession would repudiate to-day but which even in Ja’fari Shi’ism communicated itself to travellers in Persia of the seventeenth century. — Norman Daniel, Islam and the West, 1800

Categorization

• QUESTION: How did the Gabriel-error variant circulate so widely in Latin Christendom yet survive even in Ja’fari Persia and among actual Shi’ah in the 17th century? Worth chasing.