Avoid using splat (only works with symbolized hashes

app/model_factories/carto/layer_factory.rb

@@ -18,9 +18,8 @@ module Carto
         kind: 'tiled',
         options: base_layer_options.except('className', 'labels').merge(
           'type' => 'Tiled',
-          'name' => "#{base_layer_options['name']} Labels",
-          **base_layer_options['labels']
-        )
+          'name' => "#{base_layer_options['name']} Labels"
+        ).merge(base_layer_options['labels'])
       )
     end
 

app/model_factories/layer_factory.rb

@@ -47,9 +47,8 @@ module ModelFactories
         kind: 'tiled',
         options: base_layer.options.except('className', 'labels').merge(
           'type' => 'Tiled',
-          'name' => "#{base_layer.options['name']} Labels",
-          **base_layer.options['labels']
-        )
+          'name' => "#{base_layer.options['name']} Labels"
+        ).merge(base_layer.options['labels'])
       )
     end