This is a mixture of an unsuported scenario and a bug. Since you are using guid's as a primary key, and the datasource isn't connected to a service, which returns the id from an underlying datasource, you will have to provide a way for the newly created task to obtain an id. This is most easily done by providing a default value to the id field in the datasource schema/model/fields declaration:
That being said, the "Out of stack space" exception is a bug as well and we will fix it.
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