Expression Edit property node throwing an error only with LV RTE

[Chickentree]

I am using TestStand 2017 and LabVIEW 2018 f2. I have created this custom step type. Its edit VI works fine with LabVIEW Development System.

However, it throws an error when it's run with LabVIEW Run-Time Engine. The error comes from an ExpressionEdit property node in one of the sub VIs. If I disable the property node, no error occurs.

Why can't the run-time engine support the Expression Edit property node?

[Chickentree]

The culprit was Invoke Method: Default Values:Reinitialize All To Default. It was messing up the Expression Edit controls. Interestingly, it is still okay when I run it with LabVIEW Development System.