Symptoms

Key could not be found in the collection
InnerException: An unexpected error has occured while trying to resolve a value for Resolver ID 106C5886-18B1-4c09-BEB3-6F7342669D18.
InnerException: An unexpected error has occured while trying to resolve a value for Resolver ID 59F5D9BC-3B14-45ca-9C94-6FCB3C4D862F.
 

Diagnoses

The only change done to the process was switch the order of execution. The smartobjects involved also were not edited.
 

Resolution

Currently, the only workaround is to re-configure the event which throws this error and have the process re-deployed