Offset pagination skips rows when new ones arrive

Use a keyset: order by a stable column plus the primary key, and pass the last seen values as the cursor. Offsets are computed against a moving table, which is precisely why rows appear twice or vanish.

A stable machine-readable code, a human sentence, and, when the fault is the client's, which field. Stack traces help nobody outside your team, and a bare 400 turns every integration into guesswork.