Unparsable content </head> detected

Hello
I implement bpmn.js in an angular project. In development mode everything is OK and works properly. but in production mode, I got this error when I import .bpmn file to the modeler:

error Error: unparsable content </head> detected
	line: 262
	column: 62
	nested error: closing tag mismatch

this is the .bpmn file:

<?xml version="1.0" encoding="UTF-8"?>
<bpmn:definitions xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" targetNamespace="http://bpmn.io/schema/bpmn" id="Definitions_1">
  <bpmn:process id="Process_1" isExecutable="false">
    <bpmn:startEvent id="StartEvent_1"/>
  </bpmn:process>
  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Process_1">
      <bpmndi:BPMNShape id="_BPMNShape_StartEvent_2" bpmnElement="StartEvent_1">
        <dc:Bounds height="36.0" width="36.0" x="173.0" y="102.0"/>
      </bpmndi:BPMNShape>
    </bpmndi:BPMNPlane>
  </bpmndi:BPMNDiagram>
</bpmn:definitions>

And this is how I call it:

	load(): void {
		this.getExample().subscribe(data => {
			this.modeler.importXML(data).then(result => {
				console.log('success', result);
			}, (error) => console.log('error', error));
		});
	}

	public getExample(): Observable<string> {
		const url = '/assets/bpmn/diagram.bpmn'; // local
		return this._http.get(url, { responseType: 'text' });
	}

Hi,

I assume that the following:

	public getExample(): Observable<string> {
		const url = '/assets/bpmn/diagram.bpmn'; // local
		return this._http.get(url, { responseType: 'text' });
	}

probably retrieves some HTML document (which then contains a <head> element). I recommend you to debug that part of code in your application. You need to ensure to get the actual BPMN document.

You passing invalid XML,
current: unparsable content detected
improved: unparsable content detected; this may indicate an invalid BPMN 2.0 diagram file