Python Kinematics, Secondary Joints

I’m using the secondary joint function in a python kinematics script.

When the model is loaded I get the following error message where OG13 is one of several secondary joints:

Property “Controller::OG13” in “Controller::OG13” is not found. Source object is “XMINI”> “Outer-Gimbal_13”> “OG13”. Target Property is “ValueExpression”.

However the robot and its secondary joints are working fine, I only get this message, which is annoying. So why do I get this message?