The sister and mother NEVER speak TO EACH OTHER despite being on screen together multiple times.
THe only scene that pushes it over the pass line (does it really?) is when Cindy is telling Claire that she must come to such and such place. It's an intimate and congenial looking exchange but Claire does not actually respond.
I'm not gonna argue that it fails but I'm not super convinced that that line alone counts as "conversation."
Also, Claire and Cindy (a very minor character) have multiple brief conversations, including about going to tour the Maker's Mark distillery.