diff --git a/apply-failure/action.yml b/apply-failure/action.yml
index a7eceeb..ddff0cb 100644
--- a/apply-failure/action.yml
+++ b/apply-failure/action.yml
@@ -9,6 +9,8 @@ inputs:
     description: "Arguments to provide to Terraform (e.g. -var=\"key1=value1\" -var=\"key2=value2\")."
     required: false
     default: ""
+  stderr_contains:
+    description: "A string value to assert that is contained in the stderr output"
 
 runs:
   using: 'composite'
@@ -17,7 +19,6 @@ runs:
 
     # Apply the Terraform config
     - name: Terraform Apply
-      if: matrix.shells != 'true'
       id: apply
       continue-on-error: true
       shell: sh
@@ -26,8 +27,15 @@ runs:
 
     # Ensure that the outcome was a failure
     - name: Check for Failure
-      if: matrix.shells != 'true' && steps.apply.outcome != 'failure'
+      if: steps.apply.outcome != 'failure'
       shell: sh
       run: |
         echo "Apply had a status other than the expected failure: ${{ steps.apply.outcome }}"
         exit 1
+
+    - name: Check for stderr string
+      if: inputs.stderr_contains != '' && !contains(steps.apply.outputs.stderr, inputs.stderr_contains)
+      shell: sh
+      run: |
+        echo "stderr does not contain the expected string (${{ inputs.stderr_contains }})"
+        exit 1
diff --git a/matrix/action.yml b/matrix/action.yml
index 204c396..d8e295a 100644
--- a/matrix/action.yml
+++ b/matrix/action.yml
@@ -36,7 +36,7 @@ runs:
       id: images
       shell: bash
       run: |
-        images='["alpine:latest", "redhat/ubi9:latest", "fedora:latest", "centos:latest", "ubuntu:latest", "amazonlinux:latest"]'
+        images='["alpine:latest", "redhat/ubi9:latest", "fedora:latest", "centos:latest", "amazonlinux:latest"]'
         IFS=',' read -r -a additional_images <<< $(echo "${{ inputs.additional_images }}" | sed 's/[[:blank:]]//g')
         for image in "${additional_images[@]}"; do
             images=$(echo "$images" | jq -r ". + [\"$image\"]")
@@ -136,20 +136,20 @@ runs:
             minor=$(echo $version | cut -d. -f2)
             # Exclude Amazon Linux 1/2 with any version less than 14
             if ! ( [ $major -eq 0 ] && [ $minor -lt 14 ] && ( [ "$image" = "amazonlinux:1" ] || [ "$image" = "amazonlinux:2" ] )) then
-              matrix+=("{\"container\": {\"image\": \"$image\"}, \"runs-on\": \"ubuntu-latest\", \"terraform_version\": \"$version\", \"shells\": \"false\"}")
+              matrix+=("{\"container\": {\"image\": \"$image\"}, \"runs-on\": \"ubuntu-latest\", \"terraform_version\": \"$version\"}")
             fi
           done
         done
 
         # Add the Linux shell configurations
         for version in $(echo "${tf_versions}" | jq -r '.[]'); do
-          matrix+=("{\"container\": \"\", \"runs-on\": \"ubuntu-latest\", \"terraform_version\": \"$version\", \"shells\": \"true\"}")
+          matrix+=("{\"container\": \"\", \"runs-on\": \"ubuntu-latest\", \"terraform_version\": \"$version\"}")
         done
 
         # Add the non-Linux configurations
         for os in $(echo "${runners}" | jq -r '.[]'); do
           for version in $(echo "${tf_versions}" | jq -r '.[]'); do
-            matrix+=("{\"container\": \"\", \"runs-on\": \"$os\", \"terraform_version\": \"$version\", \"shells\": \"false\"}")
+            matrix+=("{\"container\": \"\", \"runs-on\": \"$os\", \"terraform_version\": \"$version\"}")
           done
         done