diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ca885d9f4af..699e17056ff 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -69,7 +69,8 @@ jobs:
     runs-on: ubuntu-latest
     needs: remainder
     # At least one plume-lib project no longer works on Java 8.
-    if: matrix.java.version != 8 || matrix.script != 'plume-lib'
+    # Java 8 does not allow toolchains, so testing 'cftests-junit-jdk21' is unnecessary.
+    if: matrix.java.version != 8 || (matrix.script != 'plume-lib' && matrix.script != 'cftests-junit-jdk21')
     permissions:
       contents: read
     strategy: