If an error happens after a human task then the transaction is rolled back and the user gets an error. Until the error is resolved the task can not be progressed.

However an error after a timer event propagates up in process hierarchy and, as it is not caught, it aborts root process and its descendants. This behavior is not acceptable.

Please provide a solution that enables an administrator to investigate the root cause and recover the process.

As a general approach errors should be caught and problems brought to the attention of an administrator for manual resolution.