同一目录下Python包为何通过__version__与pip显示版本不一致？

我已仔细检查环境，两种方法显示的包目录一致：

>>> !pip show astropy
Name: astropy
Version: 5.1
Summary: Astronomy and astrophysics core library
Home-page: http://astropy.org/
Author: The Astropy Developers
Author-email: astropy.team@gmail.com
License: BSD 3-Clause License
Location: /home/duhc/anaconda3/lib/python3.9/site-packages
Requires: packaging, numpy, PyYAML, pyerfa
Required-by: sdss-marvin, photutils, mgefit, gwcs

>>> import astropy
>>> print(astropy.__version__)
>>> print(astropy.__path__)
4.3.1
['/home/duhc/anaconda3/lib/python3.9/site-packages/astropy']

可见，二者目录均为/home/duhc/anaconda3/lib/python3.9/site-packages，但版本却不相同。

内容的提问来源于stack exchange，提问作者Hangci Du