I think there is a bug in `Field.Access::_eval_subs(self, old, new)` as the `is_absolute_access` property is not copied. It should be ``` def _eval_subs(self, old, new): return Field.Access(self.field, tuple(sp.sympify(a).subs(old, new) for a in self.offsets), tuple(sp.sympify(a).subs(old, new) for a in self.index), is_absolute_access=self.is_absolute_access, # << this is missing, maybe there is more ... dtype=self.dtype) ``` instead of ``` def _eval_subs(self, old, new): return Field.Access(self.field, tuple(sp.sympify(a).subs(old, new) for a in self.offsets), tuple(sp.sympify(a).subs(old, new) for a in self.index), dtype=self.dtype) ``` Otherwise when performing sympy substitutions, that property might get lost and subsequent `resolve_field_access()` endeavors may produce garbage.