Minimal example:

import os
import shutil
from distutils import dir_util

shutil.rmtree('folder1')

os.makedirs('folder1/folder2/folder3/')
with open('folder1/folder2/folder3/data.txt', 'w') as fp:
    fp.write('hello')
    
print(os.path.exists('folder1/new_folder2')) # -> prints false
dir_util.copy_tree('folder1/folder2', 'folder1/new_folder2') # -> works

shutil.rmtree('folder1/new_folder2')
print(os.path.exists('folder1/new_folder2')) # -> prints false
dir_util.copy_tree('folder1/folder2', 'folder1/new_folder2') # -> crashes

---------------------------------------------------------------------------
FileNotFoundError                         Traceback (most recent call last)
/opt/conda/lib/python3.7/distutils/file_util.py in _copy_file_contents(src, dst, buffer_size)
     40         try:
---> 41             fdst = open(dst, 'wb')
     42         except OSError as e:

FileNotFoundError: [Errno 2] No such file or directory: 'folder1/new_folder2/folder3/data.txt'

dir_util caches folders it previously created in a static global variable _path_created which is a bad idea:
https://github.com/python/cpython/blob/master/Lib/distutils/dir_util.py

Distutils is now deprecated (see PEP 632) and all tagged issues are being closed. From now until removal, only release blocking issues will be considered for distutils.

If this issue does not relate to distutils, please remove the component and reopen it. If you believe it still requires a fix, most likely the issue should be re-reported at https://github.com/pypa/setuptools