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).


super(One2many, self).__init__(
            comodel_name=comodel_name,
            inverse_name=inverse_name,
            string=string,
            **kwargs
        )
    def _setup_regular_full(self, model):
        super(One2many, self)._setup_regular_full(model)
        if self.inverse_name:
            
            comodel = model.env[self.comodel_name]
            invf = comodel._fields[self.inverse_name]
            
            
            
            if isinstance(invf, Many2one):
                model._field_inverses.add(self, invf)
                comodel._field_inverses.add(invf, self)
    _description_relation_field = property(attrgetter('inverse_name'))
    def convert_to_onchange(self, value, record, fnames=()):
        fnames = set(fnames or ())
        fnames.discard(self.inverse_name)
        return super(One2many, self).convert_to_onchange(value, record, fnames)
    def check_schema(self, model):
        if self.comodel_name in model.env:
            comodel = model.env[self.comodel_name]
            if self.inverse_name not in comodel._fields:
                raise UserError(_("No inverse field %r found for %r") % (self.inverse_name, self.comodel_name))
    def read(self, records):