error when proxy request which code is 304

[yumiguan]

Traceback (most recent call last):
 File "venv/lib/python3.8/site-packages/flask/helpers.py", line 166, in generator
gen.close()
 File "venv/lib/python3.8/site-packages/flask/ctx.py", line 464, in __exit__
self.auto_pop(exc_value)
 File "venv/lib/python3.8/site-packages/flask/ctx.py", line 452, in auto_pop
self.pop(exc)
 File "venv/lib/python3.8/site-packages/flask/ctx.py", line 438, in pop
app_ctx.pop(exc)
 File "/venv/lib/python3.8/site-packages/flask/ctx.py", line 241, in pop
 assert rv is self, "Popped wrong app context. (%r instead of %r)" % (rv, self)

AssertionError: Popped wrong app context. (None instead of <flask.ctx.AppContext object at 0x10b977280>)
Exception ignored in: <generator object stream_with_context.<locals>.generator at 0x10bac13c0>