diff --git a/.gitea/workflows/compose-release.py b/.gitea/workflows/compose-release.py
index bad8d99..c82463f 100644
--- a/.gitea/workflows/compose-release.py
+++ b/.gitea/workflows/compose-release.py
@@ -50,7 +50,11 @@ def prepare(source_file):
         image_repo = reference.split('@')[0].rsplit('/', 1)
         image_repo[-1] = image_repo[-1].split(':')[0]
         image_repo = '/'.join(image_repo)
-        if image_repo in release['images']:
+        # Nextcloud AIO validates the mastercontainer image reference and rejects
+        # a digest. Keep its configured tag so AIO can start and manage its stack.
+        if project == 'nextcloud' and service == 'nextcloud-aio-mastercontainer':
+            pinned = reference
+        elif image_repo in release['images']:
             pinned = image_repo + '@' + release['images'][image_repo]
         elif os.environ.get('REFRESH_IMAGES') != 'true' and reference in locks:
             pinned = locks[reference]