Thanks Tihomir,
I am happy to help reporting. However, I do not want to spam your issue tracker. So far, most of my findings were known issues already.
Regarding the example.
It seems like the engine does not accept a event based gateway to have any entities inside. Incoming and Outgoing edges within the gateway are not parsed.
This is what oryx would probably produce, since gateways usually have the incoming and outgoing edges inside:
<bpmn2:eventBasedGateway id="_DF4A4948-3BEF-4E89-869E-8D44E1541900" name="Should be event split" gatewayDirection="Diverging">
<bpmn2:incoming>_C763BDA9-C7BA-4308-A6B1-746CA4ABE974</bpmn2:incoming>
<bpmn2:outgoing>_DE06FFCD-C6F8-4F01-8EC8-BCED4B8FC022</bpmn2:outgoing>
<bpmn2:outgoing>_847F1835-11D2-4D6E-A06B-FCEB3733DC34</bpmn2:outgoing>
</bpmn2:eventBasedGateway>
This is what the designer produces:
<eventBasedGateway id="_2" name="Split" gatewayDirection="Diverging" />
The sequence Flows are not within the process tags, but not within the gateway>
<sequenceFlow id="_11-_2" sourceRef="_11" targetRef="_2" />
<sequenceFlow id="_2-_3" sourceRef="_2" targetRef="_3" />
<sequenceFlow id="_2-_4" sourceRef="_2" targetRef="_4" />
The xml of the designer works.