Short story: "The Memory Nobody Returned"

The memory rental shop was on the second floor across from the station. A day with someone else's memory cost ten dollars. Most people rented the sea. A sea they had never been to, a sea seen for the first time, a sea seen with someone.

Sujin had rented the same memory for three years. A summer afternoon at twelve, an old woman she did not know cutting a watermelon for her. Nobody knew whose memory it was. The clerk said it was "a memory that was never returned": its owner had left it there and never came back for it.

"What happens if they never come back?"
"If nobody claims it for long enough, it belongs to the last person who rented it."

That day, for the first time, Sujin did not return the memory. Instead she listened for one more day to the knife going through the watermelon, to the cicadas falling silent on the wooden porch. The next day she taped a note to the shop door.

"To whoever left the memory of the grandmother with the watermelon, the summer you were twelve: I am keeping it safe. When you come for it, there is something I would like to leave with you, too."

Note: people say "AI stories always end warmly", so I asked for a rewrite that leaves the ending open. Tell me where it feels clichéd.