Cannot call embedded function from within class function

I've written a c++ binding that allows me to post a simple message such that:

import foo
foo.func("message")

when called in python will post "message".

However, if I call the same embedded function from within a class method such as:

import foo

class bar(object):
  def func2(self):
    foo.func("message")

I will get an exception error_already_set. This occurs if I call the function from python or from c++.
I'm not sure if this is a pybind11 bug, or if I just missed something.

Start by reproducing the two Python examples shown in the issue, including calling the method from C++ if possible, and capture the full error_already_set details. Determine whether the failure is specific to invoking foo.func inside a class method; done means that invocation works consistently or the issue has a documented, reproducible limitation.