diff --git a/pipeline/frontend/yaml/compiler/settings/params.go b/pipeline/frontend/yaml/compiler/settings/params.go
index 9bbeb5d49..a021d3daa 100644
--- a/pipeline/frontend/yaml/compiler/settings/params.go
+++ b/pipeline/frontend/yaml/compiler/settings/params.go
@@ -111,6 +111,11 @@ func sanitizeParamValue(v interface{}, secrets map[string]string) (string, error
 			for i := 0; i < vv.Len(); i++ {
 				v := vv.Index(i).Interface()
 
+				// if we handle a list with a nil entry we just return a empty list
+				if v == nil {
+					continue
+				}
+
 				// ensure each element is not complex
 				if isComplex(reflect.TypeOf(v).Kind()) {
 					containsComplex = true
diff --git a/pipeline/frontend/yaml/compiler/settings/params_test.go b/pipeline/frontend/yaml/compiler/settings/params_test.go
index 22ab60aa5..37ec227ae 100644
--- a/pipeline/frontend/yaml/compiler/settings/params_test.go
+++ b/pipeline/frontend/yaml/compiler/settings/params_test.go
@@ -59,6 +59,11 @@ func TestParamsToEnv(t *testing.T) {
 	got := map[string]string{}
 	assert.NoError(t, ParamsToEnv(from, got, secrets))
 	assert.EqualValues(t, want, got, "Problem converting plugin parameters to environment variables")
+
+	// handle edge cases (#1609)
+	got = map[string]string{}
+	assert.NoError(t, ParamsToEnv(map[string]interface{}{"a": []interface{}{"a", nil}}, got, nil))
+	assert.EqualValues(t, map[string]string{"PLUGIN_A": "a,"}, got)
 }
 
 func TestSanitizeParamKey(t *testing.T) {