Django Model QuerySet: RuntimeError generator raised StopIteration - django

Question

I've recently updated my Django to version 2.2.4 and python to 3.7,
and I encounter this error randomly:
Traceback (most recent call last):
File "/foo/venv/lib/python3.7/site-packages/django/db/models/query.py", line 73, in __iter__
obj = model_cls.from_db(db, init_list, row[model_fields_start:model_fields_end])
File "/foo/venv/lib/python3.7/site-packages/django/db/models/base.py", line 511, in from_db
for f in cls._meta.concrete_fields
File "/foo/venv/lib/python3.7/site-packages/django/db/models/base.py", line 511, in <listcomp>
for f in cls._meta.concrete_fields
StopIteration
I tried to debug the code to find out what's happening, and it seems the from_db function in django.db.models.base.py is causing this error:
# /foo/venv/lib/python3.7/site-packages/django/db/models/base.py
...
#classmethod
def from_db(cls, db, field_names, values):
if len(values) != len(cls._meta.concrete_fields):
values_iter = iter(values)
values = [
next(values_iter) if f.attname in field_names else DEFERRED
for f in cls._meta.concrete_fields
]
new = cls(*values)
new._state.adding = False
new._state.db = db
return new
...
next(values_iter) is raising this error and it seems that Django devs should surround that with try except block to make this work in python 3.7,
but my question is, is there a way to overcome this issue as a temp fix or not?
thanks.
Update#1:
I've found out when exactly this error happens, When I call .values_list('myfield', flat=True) on a QuerySet, the query changes to SELECT myfield from ... and this breaks everything.