diff --git a/.github/actions/report-coverage/action.yml b/.github/actions/report-coverage/action.yml
index 0658f9a..b7e2b1b 100644
--- a/.github/actions/report-coverage/action.yml
+++ b/.github/actions/report-coverage/action.yml
@@ -23,7 +23,7 @@ runs:
     - name: Combine coverage & fail if it's <${{inputs.fail_under}}.
       shell: bash
       run: |
-        python -Im coverage combine || true
+        python -Iim coverage combine || true
         python -Im coverage html --skip-covered --skip-empty
 
         # Report and write to summary.