Ijma Of Usuliyyun
Ijma on the Sunan he listed is evident. need not to prove.
I can give you many examples actually. Christianity is the biggest example itself. Judaism too. One could argue for Hinduism perhaps also. The Mandela effect may be of importance here also
The history of misconception of Christianity is well known. The crucifixion of Jesus is reported by some spectators, and the doctrine of trinity and redemption is expounded by St Paul. They do have the claim of Ijma on them in the very beginning. Ijma is needs to be Ijma on the very first stage.