SQL*Loader-128: unable to begin a session ORA-01017: invalid username/password; logon denied

When submitting a custom concurrent program this fails intermittently with the following error SQL*Loader-128: unable to begin a session
ORA-01017: invalid username/password; logon denied

The username and password are not pass through the sql loader control file they are calling it through concurrent request. 

As a workaround we've tried to bounce the CM, it works, but this is not an acceptable solution, as this solution only works for about 3 days, after this the programs starts failing again

This is some of the things we've tried/research:

- Parameter processes it has been changed from 1528 to 2000 in the init.ora file