Add Message Start Event (non-interrupting) inside SubTask by-default

In this case (isInterrupting: false instead of isInterrupting: ‘false’):
When I dragging (ie not placed yet) the SubTask, it looks like:
image
And when I placed it looks like:
image
In XML:
image
Currently I’m using following versions:

    "bpmn-js": "8.1.0",
    "bpmn-js-properties-panel": "0.38.1",
    "camunda-bpmn-moddle": "4.5.0",
    "diagram-js": "7.1.0",

So, as you can see, if I pass to the “isInterrupting” property “false” as a boolean value, it even won’t write to the XML. “eventDefinitionType” too, has no effect. It looks like a bug.
Here is the full listing:

And fun note:
If I’ll pass “0” (as a number) to the “isInterrupting” property, everything is working as it should (except the fact, that there is 0 instead of false (0 == false in terms of JS)).
Just try (if you can) the following code:

    const startEvent = this.elementFactory.createShape({
      type: 'bpmn:StartEvent',
      x: 40,
      y: 82,
      name: '',
      parent: subProcess,
      isInterrupting: 0,
      businessObject: this.bpmnFactory.create('bpmn:StartEvent'),
      eventDefinitionType: 'bpmn:MessageEventDefinition'
    })

But in this case, zero will be writed to the XML as well, and it’s not ok for the backend side.
I guess, there is issue with type recognition / casting.