## Summary
<!--Explain briefly what goes wrong and explain why you believe this is a bug and not the intended behavior of SQLite (if it is not a crash).-->**No review yet**

## Minimized query

```sql
ATTACH DATABASE ':memory:' AS aux28;
CREATE TABLE t1(a INT, b INT);
INSERT INTO t1(a,b) VALUES(1,null),(null,null),(1,null); /* PRAGMA read_uncommitted = TRUE; */ CREATE UNIQUE INDEX t1b ON t1(abs(b));
SELECT quote(a), /**/ quote(b), '|' FROM t1 GROUP BY a, abs(b);

REINDEX;
UPDATE t1 SET b = json_object('k', b) WHERE b IS NOT NULL RETURNING *;
SELECT STRING_AGG(b, '|') FROM t1;
DETACH DATABASE aux28;
VACUUM main;
CREATE TEMPORARY  VIEW IF NOT EXISTS v_t1_9088 AS SELECT b FROM t1;
```

## Actual output

```sql
NULL|NULL||
1|NULL||
```

## Expectation

```sql

```

## Flag

```

```

