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
else:
                        
                        env = records.env(user=SUPERUSER_ID, context={'active_test': False})
                        target0 = env[model_name].search([(path, 'in', records.ids)])
                    if target0:
                        for field in stored:
                            
                            target = target0 - records.env.protected(field)
                            if not target:
                                continue
                            spec.append((field, target._ids))
                            
                            
                            if field.compute_sudo:
                                target = target.with_env(records.env(user=SUPERUSER_ID))
                            else:
                                target = target.with_env(records.env)
                            target._recompute_todo(field)
                
                for field in fields:
                    spec.append((field, None))
        return spec
    def modified_draft(self, records):
        """ Same as :meth:`modified`, but in draft mode. """
        env = records.env
        
        
        spec = []
        for field, path in records._field_triggers[self]:
            if not field.compute: