'Unexpected error encountered: java.lang.NullPointerException' when completing a human task in BPMS 6.0.1.ER1. See the attached screenshot. There is no error in server log.

I have added user guest (guest=b5d048a237bfd2874b6928e1f37ee15e) of group admin. I have prepared my environment using these REST commands:

curl -X POST -u "guest:guest" -H "Content-Type: application/json" -d '

{"name":"jbpm-playground","description":"","userName":"","password":"","requestType":"new","gitURL":""}

' http://localhost:8080/business-central/rest/repositories/

curl -X POST -u "guest:guest" -H "Content-Type: application/json" -d '

{"name":"bpms-assets","description":"","userName":"","password":"","requestType":"clone","gitURL":"git://git.app.eng.bos.redhat.com/bpms-assets.git"}

' http://localhost:8080/business-central/rest/repositories/

curl -X POST -u "guest:guest" -H "Content-Type: application/json" -d '

{"name":"qe","description":"","owner":"guest"}

' http://localhost:8080/business-central/rest/organizationalunits/

curl -X POST -u "guest:guest" -H "Content-Type: application/json" http://localhost:8080/business-central/rest/organizationalunits/qe/repositories/bpms-assets/

curl -X POST -u "guest:guest" -H "Content-Type: application/json" -d '

{"name":"","value":""}

' http://localhost:8080/business-central/rest/repositories/bpms-assets/projects/bpms-perf/maven/deploy/

I used GUI to start the HumanTask process and to start and complete a human task. The human task is completed and process instance correctly ends, so there seems to be no problem related to functionality.

My env:
BPMS 6.0.1.ER1