Python-future: `futurize **/*.py` does not work on deeply nested repositories with bash or zsh

I'm trying to use futurize https://github.com/suchow/Dissertate from the root directory of the repo and it returns

$ futurize --stage1 **/*.py
RefactoringTool: Skipping implicit fixer: idioms
RefactoringTool: Skipping implicit fixer: ws_comma
RefactoringTool: No files need to be modified.

I know there are bad print (python2 only) statements within assets/schools/Generic/generic.py (specifically print "" in https://github.com/suchow/Dissertate/blob/master/assets/schools/Generic/generic.py#L11 ). I could fix it manually, but I was actually using this as a test to make sure that futurize could reach arbitrarily deep into the file structure that is mostly not python files, but does have python files eventually.

I'm using bash as my shell, and I tried zsh $(futurize --stage1 **/*.py) as well, and both return that no files need to be modified.

If I cd assets/schools/ then it works:

futurize --stage1 **/*.py
RefactoringTool: Skipping implicit fixer: idioms
RefactoringTool: Skipping implicit fixer: ws_comma
RefactoringTool: Refactored Generic/generic.py
--- Generic/generic.py  (original)
+++ Generic/generic.py  (refactored)
@@ -1,4 +1,5 @@
 #!/usr/bin/env python
+from __future__ import print_function
 from docx import Document


@@ -8,7 +9,7 @@
         self.document = Document('../assets/word-base/dissertate.docx')

     def fill(self):
-        print ""
+        print("")

     def save(self):
         self.document.save('dissertation.docx')
RefactoringTool: Files that need to be modified:
RefactoringTool: Generic/generic.py

So it must be something having to do with the recursive search.