diff --git a/.github/workflows/test_fast.yml b/.github/workflows/test_fast.yml
index 0664b66a841..b7c6198c129 100644
--- a/.github/workflows/test_fast.yml
+++ b/.github/workflows/test_fast.yml
@@ -71,6 +71,8 @@ jobs:
           pytest tests/unit
 
       - name: Bandit
+        if: ${{ matrix.python-version == '3.7' }}
+        # https://github.com/PyCQA/bandit/issues/658
         run: |
           bandit -r --ini .bandit cylc/flow