diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 007753e4d7af462be9cb290511d2538d17bd24c9..946ff3b118a645e8d78c8489789480c60e8c0d94 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -69,6 +69,7 @@ Python 3.6 POCL:
 
 Python 3.5 Conda:
   script:
+  # Disable caching to ensure SymEngine code generation is exercised.
   - export SUMPY_NO_CACHE=1
   - export SUMPY_FORCE_SYMBOLIC_BACKEND=symengine
   - CONDA_ENVIRONMENT=.test-conda-env-py3.yml