The route reaches the final bridge COOP, then changes letter 1 to reach POOP. Its 5 moves match the dictionary distance calculated from the target.
Compare the first move
CRIB has 1 accepted one-letter neighbors in this vocabulary. 1 can begin a shortest route: CRAB. Each leaves exactly 4 moves to POOP.
Similarity can be misleading
CRIB → CRAB does not reduce the number of letters that differ from POOP, but still belongs to a minimum-move route. Reachable word connections matter more than matching letters immediately.
If a word is rejected
Enter the last accepted word in the solver, exclude the rejected word, and recalculate. A shorter dictionary can require more moves. Read the strategy guide for a worked detour example.