There is an error in Change processor because of the issue.projectKey variable used in nodeHelper.getIssueType
In comparison with Create processor where you can use issue.projectKey in Change Processor you have to use issue.project.key
Check the Sync Rules and correct the code as showed below.
In the Incoming sync for existing issues(change processor) replace this codewith this code
For more details check getIssueType nodeHelper method reference.