diff --git a/internal/service/auto_config.go b/internal/service/auto_config.go
index 10675e5..ae31894 100644
--- a/internal/service/auto_config.go
+++ b/internal/service/auto_config.go
@@ -400,6 +400,7 @@ func (s *AutoConfigService) BuildPipeline(req AutoConfigRequest, deploy bool) (*
     }
 
     // ---- 4. Create recognition units for each video source ----
+    editor.Instances = editor.Instances[:0] // clear previous instances on re-deploy
     for _, srcName := range cleanSources {
         unitName := deriveSafeInstanceName(srcName)
         inst := ConfigProfileInstanceEditor{