I suspect this is caused by bundler-cache: true in the workflow.

On a terminal, this might be a moment for bundle clean -force
Since this is GitHub, I'm going to make a test pr that alters the yml doc for the deploy workflow.

Author: katyhuff

.github/workflows/deploy-site.yml

@@ -21,7 +21,7 @@ jobs:
         uses: ruby/setup-ruby@v1
         with:
           ruby-version: 2.0
-          bundler-cache: true
+          bundler-cache: false
 
       - name: Build the website source
         run: bundle exec rake generate