How could we find out this bug?

If you invoke repositoryService.suspendDeployment(deploymentDbid), you will find out that the state of relative tasks is still 'open'.

Because there is a duplicated field 'state' in both TaskImpl and ScopeInstanceImpl. when we invoke 'taskImpl.suspend()' method, this method is defined in ScopeInstanceImpl.

in this method, the 'state' of ScopeInstanceImpl field will be changed to 'suspend', but the 'state' of TaskImpl field still be 'open', so in the end, no matter how we invoke the suspend() method, the TaskImpl is still open, it won't be suspended.

So I think we should delete the duplicated field 'state' of TaskImpl.