NOJIRA:  Enhancements to logging & error handling related to how DLM dec...

...ides whether a user receives a fragment;  should make troubleshooting much clearer

When issues occur, the current code produces stack traces in the logs that don't name fragments, groups, or user accounts.  These omissions make it hard to narrow your search for the cause of an issue, such as a missing group.
Agreed.  FWIW I didn't touch line line earlier b/c it's not a part of the functional delta (only whitespace delta due to being wrapped in try/catch).