diff --git a/modules/services/x11/display-managers/default.nix b/modules/services/x11/display-managers/default.nix
index 54ed4dec218..2582679e9e7 100644
--- a/modules/services/x11/display-managers/default.nix
+++ b/modules/services/x11/display-managers/default.nix
@@ -156,8 +156,7 @@ in
 
       job = mkOption {
         default = {};
-        type = types.optionSet;
-        merge = mergeOneOption;
+        type = types.uniq types.optionSet;
         description = "This option defines how to start the display manager.";
 
         options = {