diff --git a/src/core/receiver/gnss_block_factory.cc b/src/core/receiver/gnss_block_factory.cc
index 666c1953b..164e22d8c 100644
--- a/src/core/receiver/gnss_block_factory.cc
+++ b/src/core/receiver/gnss_block_factory.cc
@@ -226,7 +226,11 @@ auto findRole(const ConfigurationInterface* configuration, const std::string& ba
     // Current behavior: if there is no "Tag0" use "Tag" instead
     if (ID < 1 && !configuration->is_present(role + impl_prop))
         {
-            return base;  //  legacy format
+            const auto stub = configuration->property(role + impl_prop, ""s);
+            if (stub.empty())
+                {
+                    return base;
+                }
         }
 
     return role;