Put 11/12/2026 on a fictional U.S. equipment-rental request and ask AI to translate it into Chinese. If the intended date is November 12, a translation saying December 11 changes the delivery date. Both are valid calendar dates, so a basic format check may miss the problem. This synthetic example concerns cross-language handoffs, not a reported customer incident.

For a slash-separated date, retain the original string and the source field’s documented format. If the format was not explicitly agreed, ask the submitter to confirm the month and day rather than letting a model guess from the surrounding language. After confirmation, keep both the verified date and the original. Translation can change the presentation, but it cannot replace factual confirmation.

MDN explains that an HTML date input’s display depends on the browser locale, while its value uses yyyy-mm-dd. A review sheet can therefore show November 12, 2026 and 2026 年 11 月 12 日, while the interface stores 2026-11-12. These forms should identify the same day. A screenshot alone does not establish what value was submitted.

A delivery date may identify only a calendar day. RFC 3339 separately defines full-date and date-time, the latter including a time and offset. Do not invent midnight UTC merely to fit a field and then convert it to a local time zone. If the business needs a delivery deadline at a specific instant, confirm the time and zone separately instead of asking AI to create them.

Our proposed acceptance test uses an ambiguous slash-separated date, a date with an explicit month name and an impossible date. Send fictional data through input, translation, storage and export, inspecting the actual value at each stage. Record which inputs need clarification and which should be rejected. This is a proposed test plan, not a test performed on a customer system.

On the handoff sheet, place the original, the confirmed year-month-day and the destination field side by side, with the person who confirmed the meaning. Checking only whether the translation reads smoothly can miss a changed business fact. Make date awaiting confirmation a visible state. An unanswered question is preferable to turning a fluent guess into a formal commitment.