Linux env python no module name, wtf?

Question

linux

I suddenly encountered such a problem: there is a python script that collects certain data, it worked perfectly, but suddenly it broke.
In the first line specified!/usr/bin/env python3
In a script there are import requests
Actually there was a ModuleNotFoundError error. If you specify !/usr/bin/python3, everything works.
What could be the problem?

Answer 1

In the first case, you run python specified in the path from environment variables, in the second case, you run a very specific python3 interpreter file.
In the general case, these can be two different interpreters located in different paths and using their own libraries

Answer 2

You probably have two installations of python3.
What does
which python3 give
?