Fool Me Once: What is the plot hole in the series and what did Harlan Coben say about it?

A Fool Me Once plot hole has been questioned by fans who were left a little bit confused after finishing the Netflix series.

A limited series adapted from the Harlan Coben novel, Fool Me Once was released on January 1st and fans were gripped by the series starring Michelle Keegan, Richard Armitage, and Joanna Lumley.