I am not sure what it was that triggered it. I was using cawemo for about an hour and then it just stopped displaying labels I was creating on tasks, events etc. exactly as in the OP. However, when I uploaded the bpmn file to bpmn.io it worked fine. I did some work and then exported from bpmn.io and imported into cawemo overwriting the diagram that had the problem above and the same diagram no longer had the issue!