diff --git a/.github/workflows/testing.yaml b/.github/workflows/testing.yaml
index 63e50ea2..27d839f2 100644
--- a/.github/workflows/testing.yaml
+++ b/.github/workflows/testing.yaml
@@ -45,11 +45,14 @@ jobs:
       with:
         python-version: ${{ matrix.python-version }}
 
-    - name: poetry cache # Change CACHE_STRING secret to bust the cache. Useful with minor Python version changes.
+    - name: Capture full Python version in env
+      run: echo "PYTHON_FULL_VERSION=$(python --version)" >> $GITHUB_ENV
+
+    - name: poetry cache # Change CACHE_STRING secret to bust the cache
       uses: actions/cache@v2
       with:
         path: .venv
-        key: ${{ runner.os }}-${{ hashFiles('poetry.lock') }}-${{ matrix.python-version }}-${{ secrets.CACHE_STRING }}
+        key: ${{ runner.os }}-${{ hashFiles('poetry.lock') }}-${{ env.PYTHON_FULL_VERSION }}-${{ secrets.CACHE_STRING }}
 
     - name: Install dependencies
       run: |