While looking at how timeouts would get set, I noticed that the cached used at https://github.com/dimagi/dimagi-utils/blob/master/dimagi/utils/django/cached_object.py#L244 is type dimagi.test_utils.cache_tests.FakeCache.  It looks like MOCK_REDIS_CACHE is being set to a non-None value, but I only see it being set in the cache tests => I am puzzled.