If you have the Twin Otter for MSFS, run the tool manager to get the update v126.96.36.199.
Aerosoft detailed the fixes and the main target is the improvement of the aircraft response to the pitch control input and the flight behaviour with center of gravity and inertia values enhancements.
- Lower elevator down sensitivity to be more balanced with up sensitivity
- CoG adjusted
- Inertia values decreased to have very low pitch jumping effect