diff --git a/src/cmsplugin_blurp/renderers/data_source.py b/src/cmsplugin_blurp/renderers/data_source.py
index 5d1fb42..4d7a040 100644
--- a/src/cmsplugin_blurp/renderers/data_source.py
+++ b/src/cmsplugin_blurp/renderers/data_source.py
@@ -128,6 +128,7 @@ class TemplateSourcesRenderer(Renderer):
     def get_sources(self, context):
         for source in self.config['sources']:
             slug = '{0}.{1}'.format(self.slug, source['slug'])
+            source = source.copy()
             source['url'] = template.Template(source['url']).render(context)
             result = source.get('default', {})
             result['data'] = Data(slug, self.config, source, context)