1. `copy_cache` in `models.py` recursively copies the caches to environment, 
2. which in
```python
def _compute_related(self, records):
        """ Compute the related field ``self`` on ``records``. """
        others = records.sudo() if self.related_sudo else records
        if records.env != others.env:
            copy_cache(records - records.filtered('id'), others.env)
        values = list(others)
        for name in self.related[:-1]:
            values = [first(value[name]) for value in values]
        for record, value in zip(records, values):
            record[self.name] = value[self.related_field.name]
```
3. copies failing cache values that have been produce previously by this line:

`models.py : def _prefetch_field()`
```python

        try:
            # THIS ONE
            result = records.read([f.name for f in fs], load='_classic_write')
        except AccessError:
            # not all records may be accessible, try with only current record
            result = self.read([f.name for f in fs], load='_classic_write')
```
I checked it's exactly the same `FailedValue` object, which is later accessed without intent (not refreshed) by the fact that the buggy environment is copied to sudo (and not refreshed).


clauses, params, tables = comodel.env['ir.rule'].domain_get(comodel._name)
            cond = " AND ".join(clauses) if clauses else "1=1"
            query = """ DELETE FROM {rel} USING {tables}
                        WHERE {rel}.{id1} IN %s AND {rel}.{id2}={table}.id AND {cond}
                    """.format(table=comodel._table, tables=','.join(tables), cond=cond, **parts)
            cr.execute(query, [tuple(records.ids)] + params)
        for act in (value or []):
            if not isinstance(act, (list, tuple)) or not act:
                continue
            if act[0] == 0:
                lines = records.mapped(lambda record: comodel.create(act[2]))
                link(lines.ids)
            elif act[0] == 1:
                comodel.browse(act[1]).write(act[2])
            elif act[0] == 2:
                comodel.browse(act[1]).unlink()
            elif act[0] == 3:
                unlink([act[1]])
            elif act[0] == 4:
                link([act[1]])
            elif act[0] == 5:
                unlink_all()
            elif act[0] == 6:
                unlink_all()
                link(act[2])
class Serialized(Field):