update by secondary index does not update the primary value

```ts
await db.offices.update({
  where: { name: "o1" },
  data: {
    address: "o1a",
  },
})
console.log(
  await db.offices.findMany({ where: { name: "o1" } })
)
// GOOD: [{ id: "XXX", address: "o1a", ... }]
console.log(
  await db.offices.findMany({ where: {} })
)
// BAD: [{ id: "XXX", ... }]
```

Is that intended?
