The dictionary is part of the puzzle
A word ladder needs more than a starting word and a target. It also needs a rule for which intermediate words are allowed. That accepted vocabulary determines which connections exist and which routes a player can actually use.
Two solvers may both use the same correct search algorithm and return different answers. If one accepts a connecting word that the other excludes, the first may find a shorter route. The disagreement starts with the inputs, not necessarily the search.
A familiar word is not a guarantee
Games make different decisions about plurals, inflected forms, abbreviations, slang, regional spellings, and uncommon words. Even a word found in a published dictionary may not appear in the list selected for a particular game.
The reverse can be surprising too: an unfamiliar word may be accepted. Before rejecting a suggested route because a word looks unusual, check it against the game. Before trusting it because every word looks ordinary, make the same check.
What a shortest-path claim really covers
A solver can establish a minimum move count for its own list. That result does not automatically establish the minimum for another list. Adding vocabulary cannot make the existing shortest route longer, but it may create a shortcut. Removing vocabulary can eliminate a route you previously relied on.
If a solver reports no solution, read it as no solution under its current vocabulary and rules. It does not prove that no English word ladder could ever connect the two endpoints.
Check a mismatch in a useful order
First, confirm the starting word and target. Next, compare every adjacent pair to make sure exactly one position changes. Then check each intermediate word in the game. Finally, count the transitions rather than the displayed words.
This sequence separates a wrong puzzle, an invalid jump, a vocabulary mismatch, and an off-by-one count. Each has a different fix. A screenshot of only the final move total usually hides the information needed to tell them apart.
Read compatibility notes before relying on a result
Useful solver documentation identifies the vocabulary source or explains its limits. Claims of exact official compatibility need evidence; a few matching examples are encouraging but do not establish that every accepted word is identical.
On an independent companion site, treat a clearly labeled practice result as a practice result. If the official game rejects a suggested word, preserve the full route and the rejected word when describing the issue. That makes the discrepancy specific enough to investigate and correct.