It should be noted that people see what they expect. Miyu did not expect Yuu to take so long, but he had psychological blinders in place. It's similar to how many people fail to recognize mutual attraction.
she accidently heard her mother said terrible thing to her grandparent. She got shocked that her loving mother could say something that terible. Not long after that, her mother pass away because of traffic incindent. That terrible thing her mother said is the last thing she could remember and thus become her trauma.
Because that, she become afraid of "change" and very protective to her "memories". Like for example, her room interior barely or didnt change since 10 year ago. Compared to mahiru and miya, i feel like Asaka is still trapped in the past and refuse to face present time