Couple of question on your issues
1) How did you promote the jobs to v12 from V10.
2) Do you have this error with one specific job or all the jobs ( Also is it related to a single platform like SAP / UNIX / WIN ) or you have the same error for all the jobs.
3) Kindly share the detailed log report to understand more about the failure and the jobs names as well.
~The default Object name size is 200 characters and ideally you should not have any issue there