Unknow workflowType in prometheus metrics

Hello to the temporal

I first want to thank you guys for the awesome project that you have created, it is one a kind.

I have come across an issue when trying to export prometheus metrics in the server. The issue is that the workflowType is unknown in the metric but that does not seem right. here is the metric line

activity_end_to_end_latency_bucket{activityType="SampleActivity",namespace="all",operation="RespondActivityTaskCompleted",taskqueue="hello_world",workflowType="_unknown_",le="0.001"} 0

while workflowType is know, observed from the web UI the json contains:

"workflowType": {
    "name": "SampleSignalWorkflow"

So my question would be , am I missing something or is this a bug ?

Seems that workflowType should not be on this metrics at all. This should be treated as a bug.

Thank you for your response.