Robert Alexander warns against treating UUIDv7’s timestamp as exact creation time or a global generation order. The RFC permits timestamp adjustment, while within-millisecond ordering, clock rollback and restarts depend on the generator. The post also reports a Python 3.14 example in which clock rollback followed by load increases the embedded timestamp’s error. UUIDv7 remains useful for approximate time sorting, but applications must separately validate required accuracy and monotonicity and must not treat identifiers as access-control secrets.