G'day. The sensors seem tuned for extra sensitivity at very low speeds and maybe get confused when the bonnet raises after acceleration and suddenly there is something nearby that has changed distance. The road! So yours might be angled down a touch too much, as a guess. Or a leaf or something is on the front of a sensor (the circles on bumpers ) and moves when car sets off. Dealer might discover something else.
Something similar happens me at one road corner where there is a drainage cover and raised pavement and inclination change. Maybe I will one day find out which is the reason.
Be interesting to know if you get resolved. Try pressing button to disable parking sensor, on the centre console, to see if that works as a temporary solution