In my experience, the transition controls in the voice properties settings often produce unexpected results and sometimes you have to try for a while, so I prefer to manually draw the desired pitch curve with the pen tool. Either in the piano roll window or in the pitch lane below. This also works in the voice’s auto mode.
The transition curve also changes when other syllables are used or notes are connected with the minus (-) sign.
@bigfoot I was able to reproduce your example relatively well using the ANRI Lite voice (English) and the syllable “a” [ax] for all notes. If I use other voices, the transitions sound completely different…