diff --git a/internal/collector/registry.go b/internal/collector/registry.go
index b71e6322f..a41766bdf 100644
--- a/internal/collector/registry.go
+++ b/internal/collector/registry.go
@@ -98,6 +98,7 @@ func (r *registry) EmptySets() []signal.Set {
 			continue
 		}
 		ss = append(ss, c.EmptySet())
+		exists[c.EmptySet().Namespace()] = empty{}
 	}
 	return ss
 }