Hi - two suggestions. First, I would try to reload the Presence bass patch you are using in case you accidentally changed a setting. I know that under the Contemporary category there are a few choices (finger full legato etc) and I believe they all play down to C1 (which is the C below the bottom E on a 4 string bass).
Second, I would look at the pitches of your bass notes in the EDIT window to see the octave they are at. In that window you can drag the note down and see how low it will play. To change the octave for a bunch of notes, rather than using "Inspector" I'd try selecting "Event" from the main menu, then "musical functions", then "transpose". You will see the change in the EDIT window.
Best of luck.