diff --git a/.github/workflows/composites/clean-space/action.yaml b/.github/workflows/composites/clean-space/action.yaml
index e110dc0c7e..69d61642fd 100644
--- a/.github/workflows/composites/clean-space/action.yaml
+++ b/.github/workflows/composites/clean-space/action.yaml
@@ -7,14 +7,6 @@ runs:
       shell: bash
       run: |
         sudo apt-get update
-        
-        
-    # temporary workaround for an error in free disk space action
-    # https://github.com/jlumbroso/free-disk-space/issues/14
-    - name: Update Package List and Remove Dotnet
-      shell: bash
-      run: |
-        sudo apt-get update
 
     - name: Free Disk Space
       uses: jlumbroso/free-disk-space@main
diff --git a/.github/workflows/maven.yaml b/.github/workflows/maven.yaml
index 6264d4c008..eb0740edf4 100644
--- a/.github/workflows/maven.yaml
+++ b/.github/workflows/maven.yaml
@@ -8,7 +8,7 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     env:
       # this might get set to true if there is an existing cache of test times
       # this happens in 'matrix-bounds-on-test-times-cache-hit'
@@ -96,7 +96,7 @@ jobs:
 
   test_when_cache_present:
     needs: [ build ]
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     env:
       SEGMENT_DOWNLOAD_TIMEOUT_MINS: 30
     # only run this one if there is a previous cache of test times
@@ -145,7 +145,7 @@ jobs:
 
   test_when_cache_missing:
     needs: [ build ]
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     env:
       SEGMENT_DOWNLOAD_TIMEOUT_MINS: 30
     timeout-minutes: 60
@@ -197,7 +197,7 @@ jobs:
         uses: ./.github/workflows/composites/run-and-save-test-times-when-cache-missing
 
   save_test_times_when_cache_missing:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     needs: [build, test_when_cache_missing ]
 
     steps:
@@ -210,7 +210,7 @@ jobs:
         uses: ./.github/workflows/composites/test-times
 
   save_test_times_when_cache_present:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     needs: [ build, test_when_cache_present ]
 
     steps: