During takeoff and initial climb, the flight directors should indicate the pitch required to climb at the V2+10 speed.
We did come across situations in testing where spiking in the user's throttle axis can cause the flight directors to indicate too great a pitch angle during takeoff and initial climb, but we worked around this by adding the "A/T THROTTLE LOCK" option on the EFB which disconnects the users throttles from the aircraft whenever the A/T is active (A/T green on the PFD).
Something I would recommend trying is to load into the aircraft on the runway. Ensure the "A/T THROTTLE LOCK" is enabled on the Aircraft page's Configuration Menu. Advance your physical throttles to 100% (fully forward), then trigger TOGA in the aircraft (click the hidden click spot on the bottom left screw on the captain's VHF NAV radios). Release the parking brakes and takeoff. With the A/T THROTTLE LOCK active, and your throttles in the fully forward position, this should negate any spiking in your throttles axis and allow the flight directors to display the correct pitch angle.
Hope that helps.
Mark - Just Flight