The Promised Neverland was lame from the start
In episode 1, Norman and Emma find Conny’s plush toy, Little Bunny™. It appears Conny had forgotten it while she was whisked away from the orphanage to her new adoptive family. Conny might still be at the tunnel that acts as the only exit from the property they live on, so Norman and Emma rush to deliver the toy.
They discover Conny’s corpse inauspiciously splayed out in the bed of a truck. I had the thought, “If I were trafficking children for secret and nefarious means, I might make a point of murdering them after the gate they had just passed through had been closed shut to prevent witnesses or escape. But maybe I’m overthinking this.”