ORA-04068 can be a result of compilation. It may be an expected behaviour in specific cases.
I mean, in most cases incidences of ORA-4068 and its associated errors are correct,
Read the following for further details ->
Troubleshooting PL/SQL Program Unit Invalidation Related Errors (e.g. ORA-4068, ORA-4065, ORA-6508, PLS-907) (Doc ID 2298084.1
Are those objects valid? Those objects that you see in the Oracle error stack, I mean.
If they are valid; since this is workflow related, you may need to bounce the Workflow Containers..
If this action doesn't solve the issue, bounce the database.
Additional reference : Workflow Services Getting Down (Doc ID 2697359.1)
Additional reference :
http://erman-arslan-s-oracle-forum.124.s1.nabble.com/ORA-04068-existing-state-of-packages-has-been-discarded-td7030.html