diff --git a/.github/workflows/test-software.eessi.io.yml b/.github/workflows/test-software.eessi.io.yml
index 5f4dd0de71..aedaadeaba 100644
--- a/.github/workflows/test-software.eessi.io.yml
+++ b/.github/workflows/test-software.eessi.io.yml
@@ -33,7 +33,48 @@ env:
       # and then allow for special cases for specific architectures
       aarch64/a64fx: []
 jobs:
+  # Checks whether this PR modifies any easystack files and, if so,
+  # determines which EESSI versions are affected.
+  # It then stores those versions as a space-separated list in an
+  # environment variable.
+  # Finally, it writes that value to GITHUB_OUTPUT using the correct
+  # heredoc format.
+  check_EESSI_version_changed_files:
+    runs-on: ubuntu-24.04
+    outputs:
+      EESSI_VERSIONS: ${{ steps.detect.outputs.EESSI_VERSIONS }}
+    steps:
+      - name: Check out software-layer repository
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+        with:
+          fetch-depth: 0  # Fetch all history for all branches and tags
+
+      - name: Detect EESSI version in modified easystack files
+        id: detect
+        run: |
+          # Fetch base branch explicitly to ensure it's available
+          git fetch origin ${{ github.base_ref }}
+
+          changed_files=$(git diff --name-only origin/${{ github.base_ref }}...HEAD)
+          echo "Files changed: $changed_files"
+
+          # Default to not checking missing software for any version
+          EESSI_VERSIONS=""
+          
+          # Check for specific versions in the changed easystack files
+          EESSI_VERSIONS=$(git diff --name-only origin/${{ github.base_ref }}...HEAD \
+            | grep -oP 'easystacks/software\.eessi\.io/\K[0-9]{4}\.[0-9]{2}' \
+            | sort -u \
+            | tr '\n' ' ')
+          echo "PR easystack changes related to EESSI VERSION: $EESSI_VERSIONS"
+          
+          # Use GITHUB_OUTPUT heredoc correctly
+          echo "EESSI_VERSIONS<<EOF" >> "$GITHUB_OUTPUT"
+          echo "$EESSI_VERSIONS" >> "$GITHUB_OUTPUT"
+          echo "EOF" >> "$GITHUB_OUTPUT"
+
   check_missing:
+    needs: check_EESSI_version_changed_files
     strategy:
       fail-fast: false
       matrix:
@@ -153,6 +194,7 @@ jobs:
               cvmfs_repositories: software.eessi.io
 
         - name: Check for missing installlations
+          if: contains(needs.check_EESSI_version_changed_files.outputs.EESSI_VERSIONS, matrix.EESSI_VERSION)
           run: |
               export EESSI_SOFTWARE_SUBDIR_OVERRIDE=${{matrix.EESSI_SOFTWARE_SUBDIR_OVERRIDE}}
               source /cvmfs/software.eessi.io/versions/${{matrix.EESSI_VERSION}}/init/bash
diff --git a/easystacks/software.eessi.io/2023.06/eessi-2023.06-eb-5.2.0-2023b.yml b/easystacks/software.eessi.io/2023.06/eessi-2023.06-eb-5.2.0-2023b.yml
index 90277f39e8..06fe9d7403 100644
--- a/easystacks/software.eessi.io/2023.06/eessi-2023.06-eb-5.2.0-2023b.yml
+++ b/easystacks/software.eessi.io/2023.06/eessi-2023.06-eb-5.2.0-2023b.yml
@@ -1,6 +1,6 @@
 easyconfigs:
-  - GROMACS-2024.3-foss-2023b-PLUMED-2.9.2.eb
+  - GROMACS-2024.3-foss-2023b-PLUMED-2.9.2.eb:
   - FEniCS-DOLFINx-Python-0.9.0-foss-2023b.eb:
       options:
         # see https://github.com/easybuilders/easybuild-easyconfigs/pull/25004
-        from-commit: 2ef62609e3e40785dfb28bcb91db143cee5924a5
\ No newline at end of file
+        from-commit: 2ef62609e3e40785dfb28bcb91db143cee5924a5
diff --git a/easystacks/software.eessi.io/2025.06/eessi-2025.06-eb-5.2.1-2025b.yml b/easystacks/software.eessi.io/2025.06/eessi-2025.06-eb-5.2.1-2025b.yml
index 1c43ec3c98..2b089c2ccd 100644
--- a/easystacks/software.eessi.io/2025.06/eessi-2025.06-eb-5.2.1-2025b.yml
+++ b/easystacks/software.eessi.io/2025.06/eessi-2025.06-eb-5.2.1-2025b.yml
@@ -18,5 +18,5 @@ easyconfigs:
         from-commit: 5af71d7a638be23b0abebe84afb52ba79894bddf
         # see https://github.com/easybuilders/easybuild-easyblocks/pull/4086
         include-easyblocks-from-commit: df3ca300d7f9193241e6bee2be3d58b103323725
-  - GDRCopy-2.5-GCCcore-14.3.0.eb
+  - GDRCopy-2.5-GCCcore-14.3.0.eb:
   - JUBE-2.7.1-GCCcore-14.3.0.eb