There is a bug in the following CU’s for Workflow Manager and Service Bus which potentially breaks your workflow manager. So have a look on the Workflow Manager server for an Access Denied error against some workflow manager databases. If I get time, I will dig a bit more into the issue.
Cumulative Update for Workflow Manager 1.0 (KB2799754)
Cumulative Update for Service Bus 1.0 (KB2799752)
The following thread describes a possible workaround for the issue.