The Incident 'message' database columns (ACT_HI_INCIDENT.INCIDENT_MSG_ and ACT_RU_INCIDENT.INCIDENT_MSG_) are defined as varchar(2000) and should allow messages of up to 2000 characters to be stored. However, all our incident messages are being truncated to 255 characters.
I have traced the source of the issue back to the org.camunda.bpm.engine.impl.persistence.entity.JobEntity class. This class defines a MAX_EXCEPTION_MESSAGE_LENGTH constant, which has a value of 255. This constant is used to truncate Job exception messages (ACT_RUN_JOB.EXCEPTION_MSG_, which is also defined as varchar(2000)). The truncated Job exception message is then used to create the Incident message in the createFailedJobIncident method.