diff --git a/lib/inventory/distributed-service/service-module.nix b/lib/inventory/distributed-service/service-module.nix
index 1dcf61719..dc597fdf4 100644
--- a/lib/inventory/distributed-service/service-module.nix
+++ b/lib/inventory/distributed-service/service-module.nix
@@ -746,7 +746,7 @@ in
                             ''
                           else
                             serviceModule.result.final.${machineName}.nixosModule
-                        ) instance.allMachines.${machineName}.services)
+                        ) instance.allMachines.${machineName}.services or { })
 
                       )
                       ++ (
diff --git a/lib/inventory/distributed-service/tests/nested_services/default.nix b/lib/inventory/distributed-service/tests/nested_services/default.nix
index 509276c9b..eb066bd68 100644
--- a/lib/inventory/distributed-service/tests/nested_services/default.nix
+++ b/lib/inventory/distributed-service/tests/nested_services/default.nix
@@ -1,4 +1,8 @@
 { clanLib, lib, ... }:
 {
   test_simple = import ./simple.nix { inherit clanLib lib; };
+
+  test_multi_machine = import ./multi_machine.nix { inherit clanLib lib; };
+
+  test_multi_import_duplication = import ./multi_import_duplication.nix { inherit clanLib lib; };
 }
diff --git a/lib/inventory/distributed-service/tests/nested_services/multi_import_duplication.nix b/lib/inventory/distributed-service/tests/nested_services/multi_import_duplication.nix
new file mode 100644
index 000000000..2d5184e78
--- /dev/null
+++ b/lib/inventory/distributed-service/tests/nested_services/multi_import_duplication.nix
@@ -0,0 +1,125 @@
+{ clanLib, lib, ... }:
+let
+  # Potentially imported many times
+  # To add the ssh key
+  example-admin = (
+    { lib, ... }:
+    {
+      manifest.name = "example-admin";
+
+      roles.client.interface = {
+        options.keys = lib.mkOption { };
+      };
+
+      roles.client.perInstance =
+        { settings, ... }:
+        {
+          nixosModule = {
+            inherit (settings) keys;
+          };
+        };
+    }
+  );
+
+  consumer-A =
+    { ... }:
+    {
+      manifest.name = "consumer-A";
+
+      instances.foo = {
+        roles.server.machines."jon" = { };
+      };
+      instances.bar = {
+        roles.server.machines."jon" = { };
+      };
+
+      roles.server = {
+        perInstance =
+          { machine, instanceName, ... }:
+          {
+            services."example-admin" = {
+              imports = [
+                example-admin
+              ];
+              instances."${instanceName}" = {
+                roles.client.machines.${machine.name} = {
+                  settings.keys = [ "pubkey-1" ];
+                };
+              };
+            };
+          };
+      };
+    };
+  consumer-B =
+    { ... }:
+    {
+      manifest.name = "consumer-A";
+
+      instances.foo = {
+        roles.server.machines."jon" = { };
+      };
+      instances.bar = {
+        roles.server.machines."jon" = { };
+      };
+
+      roles.server = {
+        perInstance =
+          { machine, instanceName, ... }:
+          {
+            services."example-admin" = {
+              imports = [
+                example-admin
+              ];
+              instances."${instanceName}" = {
+                roles.client.machines.${machine.name} = {
+                  settings.keys = [
+                    "pubkey-1"
+                  ];
+                };
+              };
+            };
+          };
+      };
+    };
+
+  eval = clanLib.inventory.evalClanService {
+    modules = [
+      (consumer-A)
+    ];
+    prefix = [ ];
+  };
+  eval2 = clanLib.inventory.evalClanService {
+    modules = [
+      (consumer-B)
+    ];
+    prefix = [ ];
+  };
+
+  evalNixos = lib.evalModules {
+    modules = [
+      {
+        options.assertions = lib.mkOption { };
+        # This is suboptimal
+        options.keys = lib.mkOption { };
+      }
+      eval.config.result.final.jon.nixosModule
+      eval2.config.result.final.jon.nixosModule
+    ];
+  };
+in
+{
+  # Check that the nixos system has the settings from the nested module, as well as those from the "perMachine" and "perInstance"
+  inherit eval;
+  expr = evalNixos.config;
+  expected = {
+    assertions = [ ];
+    # TODO: Some deduplication mechanism is nice
+    # Could add types.set or do 'apply = unique', or something else ?
+    keys = [
+      "pubkey-1"
+      "pubkey-1"
+      "pubkey-1"
+      "pubkey-1"
+    ];
+  };
+}
diff --git a/lib/inventory/distributed-service/tests/nested_services/multi_machine.nix b/lib/inventory/distributed-service/tests/nested_services/multi_machine.nix
new file mode 100644
index 000000000..520a41941
--- /dev/null
+++ b/lib/inventory/distributed-service/tests/nested_services/multi_machine.nix
@@ -0,0 +1,108 @@
+{ clanLib, lib, ... }:
+let
+  service-B = (
+    { lib, ... }:
+    {
+      manifest.name = "service-B";
+
+      roles.client.interface = {
+        options.user = lib.mkOption { };
+        options.host = lib.mkOption { };
+      };
+      roles.client.perInstance =
+        { settings, instanceName, ... }:
+        {
+          nixosModule = {
+            units.${instanceName} = {
+              script = settings.user + "@" + settings.host;
+            };
+          };
+        };
+      perMachine =
+        { ... }:
+        {
+          nixosModule = {
+            ssh.enable = true;
+          };
+        };
+    }
+  );
+  service-A =
+    { ... }:
+    {
+      manifest.name = "service-A";
+
+      instances.foo = {
+        roles.server.machines."jon" = { };
+        roles.server.machines."sara" = { };
+      };
+
+      roles.server = {
+        perInstance =
+          { machine, instanceName, ... }:
+          {
+            services."B" = {
+              imports = [
+                service-B
+              ];
+              instances."A-${instanceName}-B" = {
+                roles.client.machines.${machine.name} = {
+                  settings.user = "johnny";
+                  settings.host = machine.name;
+                };
+              };
+            };
+          };
+      };
+    };
+
+  eval = clanLib.inventory.evalClanService {
+    modules = [
+      (service-A)
+    ];
+    prefix = [ ];
+  };
+
+  evalNixos = lib.mapAttrs (
+    _n: v:
+    (lib.evalModules {
+      modules = [
+        {
+          options.assertions = lib.mkOption { };
+          options.units = lib.mkOption { };
+          options.ssh = lib.mkOption { };
+        }
+        v.nixosModule
+      ];
+    }).config
+  ) eval.config.result.final;
+in
+{
+  # Check that the nixos system has the settings from the nested module, as well as those from the "perMachine" and "perInstance"
+  inherit eval;
+  expr = evalNixos;
+  expected = {
+    jon = {
+      assertions = [ ];
+      ssh = {
+        enable = true;
+      };
+      units = {
+        A-foo-B = {
+          script = "johnny@jon";
+        };
+      };
+    };
+    sara = {
+      assertions = [ ];
+      ssh = {
+        enable = true;
+      };
+      units = {
+        A-foo-B = {
+          script = "johnny@sara";
+        };
+      };
+    };
+  };
+}