Can you confirm: By "pitch bend interval" do you actually meaning pitch bend range?.
If so, then with this particular patch, the pitch bend range is controlled by the pop-up modulation matrix (See user guide). The pitch bend range is set to 4800 cents but this can be changed to anything you like. For instance, to set the pitch bend range to 2 semi tones, set the range to 200 in the pop-up modulation matrix.