Today i faced an issue on client , error message they are having is
The text associated with this work item cannot be found in the assignee’s language, or in the default language for the system or legal entity. The workflow has stopped processing because of this error. Contact your system administrator for assistance.
The default language in Legal entity they are trying to run workflow is “FRENCH” while the work item subject is defined in Workflow configuration is in English, so when workflow trying to get the work item its get an empty value as it is other language! which causes workflow to stop.
Add a translation in all languages your are using (maybe the Company is in another language) in my case it was a company in FRENCH and the system was in English. Hope it will solve the issue