diff --git a/.github/workflows/build-ruby.yml b/.github/workflows/build-ruby.yml
index 5895265..9f9fabe 100644
--- a/.github/workflows/build-ruby.yml
+++ b/.github/workflows/build-ruby.yml
@@ -86,7 +86,7 @@ jobs:
           docker run --platform linux/x86_64 --rm ${{ steps.vars.outputs.IMAGE }}:${{ steps.vars.outputs.TAG }} ruby -e 'puts RUBY_DESCRIPTION'
           docker run --platform linux/x86_64 --rm ${{ steps.vars.outputs.IMAGE }}:${{ steps.vars.outputs.TAG }} gem --version
           docker run --platform linux/x86_64 --rm ${{ steps.vars.outputs.IMAGE }}:${{ steps.vars.outputs.TAG }} bundle --version
-          docker run --platform linux/x86_64 --rm ${{ steps.vars.outputs.IMAGE }}:${{ steps.vars.outputs.TAG }} -v "${PWD}":"${PWD}" -w "${PWD}" /bin/sh -c 'bundle install && ruby test/engines/test_encoding.rb'
+          docker run --platform linux/x86_64 --rm -v "${PWD}":"${PWD}" -w "${PWD}" ${{ steps.vars.outputs.IMAGE }}:${{ steps.vars.outputs.TAG }} /bin/sh -c 'bundle install && ruby test/engines/test_encoding.rb'
 
       # Then, build image for aarch64 which, being emulated under qemu, is slower
       #
@@ -108,7 +108,7 @@ jobs:
           docker run --platform linux/aarch64 --rm ${{ steps.vars.outputs.IMAGE }}:${{ steps.vars.outputs.TAG }} ruby -e 'puts RUBY_DESCRIPTION'
           docker run --platform linux/aarch64 --rm ${{ steps.vars.outputs.IMAGE }}:${{ steps.vars.outputs.TAG }} gem --version
           docker run --platform linux/aarch64 --rm ${{ steps.vars.outputs.IMAGE }}:${{ steps.vars.outputs.TAG }} bundle --version
-          docker run --platform linux/aarch64 --rm ${{ steps.vars.outputs.IMAGE }}:${{ steps.vars.outputs.TAG }} -v "${PWD}":"${PWD}" -w "${PWD}" /bin/sh -c 'bundle install && ruby test/engines/test_encoding.rb'
+          docker run --platform linux/aarch64 --rm -v "${PWD}":"${PWD}" -w "${PWD}" ${{ steps.vars.outputs.IMAGE }}:${{ steps.vars.outputs.TAG }} /bin/sh -c 'bundle install && ruby test/engines/test_encoding.rb'
 
       # Finally, assemble multi-arch image for a combined push to the registry
       #