diff --git a/pkg/engine/engine.go b/pkg/engine/engine.go
index e55e0d5ba4db..aa2b03ff944e 100644
--- a/pkg/engine/engine.go
+++ b/pkg/engine/engine.go
@@ -308,9 +308,7 @@ func (e *Engine) setDefaults(ctx context.Context) {
 		e.decoders = decoders.DefaultDecoders()
 	}
 
-	if len(e.detectors) == 0 {
-		e.detectors = DefaultDetectors()
-	}
+	e.detectors = append(e.detectors, DefaultDetectors()...)
 
 	if e.dispatcher == nil {
 		e.dispatcher = NewPrinterDispatcher(new(output.PlainPrinter))
diff --git a/pkg/engine/engine_test.go b/pkg/engine/engine_test.go
index 5331553a3f12..b620c5fe5b58 100644
--- a/pkg/engine/engine_test.go
+++ b/pkg/engine/engine_test.go
@@ -417,12 +417,13 @@ func TestVerificationOverlapChunk(t *testing.T) {
 	sourceManager := sources.NewManager(opts...)
 
 	c := Config{
-		Concurrency:   1,
-		Decoders:      decoders.DefaultDecoders(),
-		Detectors:     conf.Detectors,
-		Verify:        false,
-		SourceManager: sourceManager,
-		Dispatcher:    NewPrinterDispatcher(new(discardPrinter)),
+		Concurrency:      1,
+		Decoders:         decoders.DefaultDecoders(),
+		Detectors:        conf.Detectors,
+		IncludeDetectors: "904", // isolate this test to only the custom detectors provided
+		Verify:           false,
+		SourceManager:    sourceManager,
+		Dispatcher:       NewPrinterDispatcher(new(discardPrinter)),
 	}
 
 	e, err := NewEngine(ctx, &c)