“where is it inconsistent.”
*sigh* I’ll assume you’ve read the accounts of the Last Supper. Was it on the 1st night of passover. Or the day before? check your synoptic Gospels and John.
When you look for truth in the bible - think about the truth it is trying to teach. We are to learn to do the will of God.
The “how” He does/did something is for science (or in some cases miracles) the WHYS are what religion answers.
That is not an inconsistency. It is an interpretation based on not understanding the culture of that time, and how they measured the day.