diff --git a/plugins/CuraEngineBackend/StartSliceJob.py b/plugins/CuraEngineBackend/StartSliceJob.py
index f3f34f4c3d..96124a3514 100644
--- a/plugins/CuraEngineBackend/StartSliceJob.py
+++ b/plugins/CuraEngineBackend/StartSliceJob.py
@@ -281,7 +281,7 @@ class StartSliceJob(Job):
         default_extruder_position = int(Application.getInstance().getMachineManager().defaultExtruderPosition)
         result = {}
         for key in stack.getAllKeys():
-            setting_type = stack.getProperty(key, "type")
+            setting_type = stack.definition.getProperty(key, "type")
             value = stack.getProperty(key, "value")
             if setting_type == "extruder" and value == -1:
                 # replace with the default value