Fair point. Admittedly, the whole odd jobs idea was just a place holder for something more concrete. As for why the switch in occupations? Maybe, and this might thematically clash with the setting, there was an attempt on her life. Sure the villains were dealt with her confidence and or interest in the vocation/good she was doing dramatically waned. Said idea could also blend another medusa reference into her history.
Vocational path changes don't have to be something big and important. Could be as simple as Cori feeling she was getting overworked and become stressed with the job so she took a sabbatical and did some introspection.
As a little caveat, if she was an investigator it allows her to have further history with Moly because of needing to appear in court.