diff --git a/site-modules/profile/manifests/swh/deploy/worker/lister.pp b/site-modules/profile/manifests/swh/deploy/worker/lister.pp
index c6142607..62e94ff5 100644
--- a/site-modules/profile/manifests/swh/deploy/worker/lister.pp
+++ b/site-modules/profile/manifests/swh/deploy/worker/lister.pp
@@ -1,15 +1,17 @@
 # Deployment for swh-lister
 class profile::swh::deploy::worker::lister {
   $packages = ['python3-swh.lister', 'r-base-core', 'r-cran-jsonlite']
 
   package {$packages:
     ensure => present,
   }
 
   ::profile::swh::deploy::worker::instance {'lister':
     ensure       => present,
     require      => [
       Package['python3-swh.lister'],
     ],
+    merge_policy => 'first',  # do not merge configuration, take the first
+                              # encountered configuration
   }
 }