The workflow instance can not be Terminated

i found there are no Terminated event catch by exporter.
i submit two instances of one workflow

the instance of 400440 can be Terminated:

however, another instance can not be terminated:

the error text happened as i click the “cancel instance” twice

I monitor the zeebe.log of broker in docker, no log happed(it can show sql as i add log in simple exporter codes to let it print sql, and i just add logs ):

root@7f738235dbf6:/usr/local/zeebe/logs# cat zeebe.log |grep "UPDATE WORKFLOW_INSTANCE"
10:16:19.141 [exporter] [10.0.0.23:26501-zb-actors-1] INFO  io.zeebe.broker.exporter.simple-monitor - add statement of UPDATE WORKFLOW_INSTANCE SET END_ = 1559124979138, STATE_ = 'Terminated' WHERE KEY_ = 355589;
10:20:38.767 [exporter] [10.0.0.23:26501-zb-actors-1] INFO  io.zeebe.broker.exporter.simple-monitor - add statement of UPDATE WORKFLOW_INSTANCE SET END_ = 1559125238756, STATE_ = 'Terminated' WHERE KEY_ = 400440;
root@7f738235dbf6:/usr/local/zeebe/logs#

as you can see ,there is no terminated event for the 397849.

So what is the root cause?

And, i found that exporter can not receive some events in time, if i restart broker, these events can be received. My broker is in a low load, so any suggestion?

Hi @aximo, if this happens under a light load, try enabling the Debug exporter (See: https://github.com/zeebe-io/zeebe/pull/1240), and see whether the fault lies in the Simple Monitor exporter and its representation of the state, or in the event stream itself.