Bread of the Presence Conflict?

What is the Bread of the Presence?
Leviticus 24:5 "Take fine flour and bake twelve loaves of bread, using two-tenths of an ephah [a] for each loaf. 6 Set them in two rows, six in each row, on the table of pure gold before the LORD. 7 Along each row put some pure incense as a memorial portion to represent the bread and to be an offering made to the LORD by fire. 8 This bread is to be set out before the LORD regularly, Sabbath after Sabbath, on behalf of the Israelites, as a lasting covenant. 9 It belongs to Aaron and his sons, who are to eat it in a holy place, because it is a most holy part of their regular share of the offerings made to the LORD by fire."

I just wanted to point out something I found…that has been written about. You can research further,
1 Samuel 21: 1 David went to Nob, to Ahimelech the priest. Ahimelech trembled when he met him, and asked, "Why are you alone? Why is no one with you?"
Apparent conflict;
Mark 2: 26 In the days of Abiathar the high priest, he (David) entered the house of God and ate the consecrated bread, which is lawful only for priests to eat. And he also gave some to his companions."
The Mark passage is speaking of the incident when David went to the high priest asking for bread, and the only bread available was the Bread of the Presence. Mark speaks of Abiathar being the high priest, while 1 Samuel says tht Ahimelech is the high priest. Abiathar was Ahimelech’s son. Matthew and Luke both write about the same incident but clearly omit the name of the high priest in their account.
After becoming king, and Saul killed over 40 priests (of which Ahimelech was one) Abiathar became priest under David’s rule. So Mark’s verbage …. In the days of Abiathar, literally would have been correct, but this phrase would not commonly be used to describe ‘when David ate the Bread’.
Just something to chew on and research. Let me know what you have heard about this.