The technical term for this is: a mistake.
The divorced and remarried Anglican entering the Ordinariate must go through the same process as any person desiring to enter into full communion with the Church: a tribunal investigation for nullity or in circumstances where the Pauline or Petrine Privilege apply then for dissolution of the bond.
See question #15 on this Q&A page:
ordinarychurch.org/information/q-a-s