Bugfix
The operation with the form object and the model is called up in the "User-defined transaction" button. The form object is determined by searching for the overlay for the model.
However, if the form builder does not create an overlay for the model, but instead, for example, a new object is to be created that is pre-assigned using the model, the wrong form object is transferred here.
Solution
As a minimally invasive solution, the object created by the Form Builder is annotated to the FormContext and read by the "User-defined transaction".