Chartpath in gateway startup script

When I tried to start some charts manually during gateway restarting, something strange happened.
the " Batch logic" chart was placed in the global of Sequential Function Charts without any folders.

Traceback (most recent call last):
  File "<[IADemo] Startup Script>", line 14, in <module>
	at com.inductiveautomation.sfc.ChartManager.startChart(
	at com.inductiveautomation.sfc.ChartManager.startChart(
	at com.inductiveautomation.sfc.scripting.GatewayScriptingFunctions.startChart(
	at com.inductiveautomation.sfc.scripting.SfcScriptingFunctionsPyWrapper.startChart(
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(
	at java.lang.reflect.Method.invoke(

java.lang.Exception: java.lang.Exception: no chart defined at path: Batch logic

7.9.0 (b2016101208)
Oracle Corporation 1.8.0_111

Actually this script has no issues when it is executed in a button “action performed” script.
Any clues?