Looks like on WSL the errno is errno.EACCES rather than EPERM, so we just need to change the shutil._copyxattr error handler to also cope with that error code:

             except OSError as e:
-                 if e.errno not in (errno.EPERM, errno.ENOTSUP, errno.ENODATA):
+                 if e.errno not in (errno.EPERM, errno.ENOTSUP, errno.ENODATA, errno.EACCES):
                     raise

If anyone needs a workaround until this is fixed in shutil itself, you can do it by monkey-patching _copyxattr:

import errno, shutil
# have to monkey patch to work with WSL as workaround for https://bugs.python.org/issue38633
orig_copyxattr = shutil._copyxattr
def patched_copyxattr(src, dst, *, follow_symlinks=True):
	try:
		orig_copyxattr(src, dst, follow_symlinks=follow_symlinks)
	except OSError as ex:
		if ex.errno != errno.EACCES: raise
shutil._copyxattr = patched_copyxattr