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).


odoo/fields.py
""" One2many field; the value of such a field is the recordset of all the
        records in ``comodel_name`` such that the field ``inverse_name`` is equal to
        the current record.
        :param comodel_name: name of the target model (string)
        :param inverse_name: name of the inverse ``Many2one`` field in
            ``comodel_name`` (string)
        :param domain: an optional domain to set on candidate values on the
            client side (domain or string)
        :param context: an optional context to use on the client side when
            handling that field (dictionary)
        :param auto_join: whether JOINs are generated upon search through that
            field (boolean, by default ``False``)
        :param limit: optional limit to use upon read (integer)
        The attributes ``comodel_name`` and ``inverse_name`` are mandatory except in
        the case of related fields or field extensions.
    """
    type = 'one2many'
    _slots = {
        'inverse_name': None,           
        'auto_join': False,             
        'limit': None,                  
        'copy': False,                  
    }
    def __init__(self, comodel_name=Default, inverse_name=Default, string=Default, **kwargs):