Require a newer version of py3o.template. Version 0.9.11 is newest one available at the moment. The issue we were having with some ODT templates might have been fixed in an earlier version (e.g. 0.9.9) but I've only tested it with 0.9.11.

--- a/requirements.txt	Fri Apr 28 21:04:43 2017 +0200
+++ b/requirements.txt	Fri Aug 25 18:36:44 2017 +0200
@@ -1,6 +1,6 @@
 flask>=0.7
 requests
-py3o.template>=0.8
+py3o.template>=0.9.11
 py3o.renderers.pyuno>=0.3
 setuptools
 pypdf2