A conflict can end socially while remaining active in the way people plan around each other.

There is a version of resolution where the surface gets repaired and nothing else does. People are polite, the subject is dropped, and the disagreement relocates into logistics: who gets invited to what, who is told first, which meetings are arranged so the two of them never overlap. The conflict continues in the shape of the arrangements. Peace of that kind is very stable, which is what makes it hard to notice.

Look at whether any of your scheduling exists to avoid one particular person. If it does, that is the unfinished conversation, and having it is smaller than the years of arrangement it replaces.