diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 61e25941..19760a92 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -29,7 +29,11 @@ jobs:
           - x64
         num_threads:
           - 1
-          - 2
+        include:
+          - version: '1'
+            os: ubuntu-latest
+            arch: x64
+            num_threads: 2
     steps:
       - uses: actions/checkout@v2
       - uses: julia-actions/setup-julia@v1