diff --git a/.github/workflows/ruby_event_store-outbox.yml b/.github/workflows/ruby_event_store-outbox.yml
index 42e4db3928..d3ef4ab7f1 100644
--- a/.github/workflows/ruby_event_store-outbox.yml
+++ b/.github/workflows/ruby_event_store-outbox.yml
@@ -69,9 +69,6 @@ jobs:
           - ruby_version: ruby-3.0
             bundle_gemfile: Gemfile.rails_6_1
             database_url: sqlite3:db.sqlite3
-          - ruby_version: ruby-3.0
-            bundle_gemfile: Gemfile.rails_6_1
-            database_url: sqlite3:db.sqlite3
           - ruby_version: ruby-3.0
             bundle_gemfile: Gemfile.rails_6_0
             database_url: sqlite3:db.sqlite3
diff --git a/support/ci/generate b/support/ci/generate
index 042de544b7..c3c20e3c4f 100755
--- a/support/ci/generate
+++ b/support/ci/generate
@@ -424,7 +424,7 @@ class CI
   end
 
   def join(*axes)
-    axes.flatten
+    axes.flatten.uniq
   end
 
   def ruby_version(*ruby_version)