On a client's profile, **Possible duplicate → Review** opened the merge window
but stopped at the first step with "Minified React error #441". Behind it, the
merge safety check could not read some of the checkout records it has to check
before two profiles may be combined, so every merge was refused before it
started. Nothing was merged or changed while this happened.

- **The merge review works again**, from a client's profile, from the bulk
  duplicate merge, and from the Business app.
- **Clear reasons.** When a merge has to be refused — for example because the
  profile being removed owns a saved card or an unfinished checkout — the merge
  window now shows the actual reason instead of a technical error code.
- **Same safety.** Every record is still checked again inside the merge itself,
  and a merge is still rolled back completely if anything changed in between.