Almost five hundred years ago, here is Article VII from the Augsburg Confession:
Article VII. Of the Church
1 Also they teach that one holy Church is to continue forever. The Church is the congregation of saints, in which the Gospel is rightly taught and the Sacraments are rightly administered.
2 And to the true unity of the Church it is enough to agree concerning the doctrine of the Gospel and
3 the administration of the Sacraments. Nor is it necessary that human traditions, that is, rites or ceremonies, instituted by men, should be everywhere alike.
4 As Paul says: One faith, one Baptism, one God and Father of all, etc. Eph 4:5-6.
All Scripture has a higher authority than Article VII. of the Church. Or, would one disagree with the doctrine of the Apostle Paul;
1 Corinthians 1:10 The Holy Bible, Evangelical Heritage Version®, EHV®, © 2019
10 Brothers,[a] I am making an appeal to you using the name of our Lord Jesus Christ. I ask that you all express the same view and not have any divisions among you, but that you be joined together in the same mind and in the same judgment.
2 Corinthians 13:11 The Holy Bible, Evangelical Heritage Version®, EHV®, © 2019
11 Finally, brothers,[a] rejoice. Set things in order. Be encouraged. Agree with one another. Be at peace. And the God of love and peace will be with you.
[a] When context indicates it, the Greek word for brothers may refer to all fellow believers, male and female.
Carefully study the premise in the original post. Are all Lutherans expressing the same view regarding the Holy Scripture (Exodus 12:6 - "beyn ha'arbayim - "between two evenings"? Or, are Lutherans divided in this matter, contrary to the teachings of Jesus, and the Apostle to the Gentiles, the Apostle Paul? (i.e. bearing false witness to one another, i.e. lying to one another) (i.e. (Matthew 19:18); (Colossians 3:9))
Regarding the true unity of the congregation of saints within the one true faith, they should be joined together in the same mind and in the same judgement. (i.e. expressing the same view, not having divisions among them) (i.e. agree with one another, be at peace with one another)
Time to set things in order before it's too late!
In Christ’s service,
Soli Deo gloria!
Bringing Christian harmony to all the world