This is a classic case of a formula that worked perfectly until it didn't, and the culprit isn't the spreadsheet, it's the environment. The user, Shadynasty8091, has done all the right troubleshooting: time syncs, calculation settings, formatting checks. Yet the timestamp still defaults to an incorrect value. The real issue here is that NOW() is a volatile function. It recalculates every time the sheet changes, and in a shared SharePoint environment, that means every sync, every open, every save can rewrite the timestamp. The formula was never truly stamping; it was always displaying a live value that happened to look frozen because the user's workflow kept it stable. Once SharePoint introduced a change, perhaps a background refresh or a new caching behavior, that stability broke.
For anyone managing real-time data on a production floor, this is a practical warning. Volatile functions like NOW() and TODAY() are not designed for immutable audit trails. They are designed for live dashboards. The moment you need a permanent record of when a check occurred, you need a different approach. The most reliable method is a circular reference with iterative calculation enabled, or a VBA macro triggered by a cell change. Neither is elegant, but both produce a timestamp that does not change after entry. SharePoint's real-time collaboration layer only amplifies the risk: what worked in a local file may break when multiple users trigger recalculations simultaneously.
We think the user's frustration is justified, but the solution is not to find the same formula that used to work. It is to accept that spreadsheets, especially shared ones, have limits as time-stamping tools. The formula they relied on was a clever workaround, not a robust feature. This is a common pain point that points to a larger truth: traditional spreadsheets were built for static data, not live collaboration. The user needs a tool that treats timestamps as first-class, immutable events, not as formulas that can be invalidated by a Friday update. Until then, the only safe path is to decouple the stamp from the formula entirely.