“oscillator retrigger” is not the same as sync. It means that the oscillator wave is reset every time a new note is triggered. This makes any detune between two oscillators sound consistent every time the note is triggered. From the manual:

TRG (Oscillator Retrig) lets the two oscillators start each note in phase with each other. This can give a stronger and more con- sistent bass punch thanks to constructive interference, and can also change the sound character in other ways.