Steps to reproduce:

1. go to Cockpit
2. select a process definition
3. open "Job Definitions" tab
4. open suspension dialog to suspend a job definition
5. select "Delayed" to execute the suspension delayed
6. enter a date (optional)
7. click "Suspend"

Observed Behavior:
The request payload is the following one:

{ suspended: true, includeJobs: true, executionDate: "2017-09-28T11:27:16" }

Expected Behavior:
The request payload should look like this:

{ suspended: true, includeJobs: true, executionDate: "2017-09-28T11:27:16.000+02000" }

The local timezone offset is provided.