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
""" Determine the value of ``self`` for ``record``. """
        env = record.env
        if self.store and not (self.compute and env.in_onchange):
            
            if self.compute:
                
                recs = record._recompute_check(self)
                if recs:
                    
                    self.compute_value(recs)
                    
                    if recs.env != env:
                        computed = record._field_computed[self]
                        for source, target in zip(recs, recs.with_env(env)):
                            try:
                                values = target._convert_to_cache({
                                    f.name: source[f.name] for f in computed
                                }, validate=False)
                            except MissingError as e:
                                values = FailedValue(e)
                            target._cache.update(values)
                    
                    return