Before going crazy about a possible mechanical problem, consider the possibility o a rider learning curve issue

Trikes like this are "balanced" or kept upright rhe same way as regular two wheeled bikes. That is that they are brought upright by steering to bring the bike (trike) back under the rider.

Steering geometry helps, but at low speed rider input is needed. So, for someone new, it's just like teaching z child to ride on two wheels.

Test ride yourself on a sloped parking lot and see if it can properly balance when coasted downhill. If so, keep in mind that the damper isn't there to steer the trike, but to insulate it from the side forces pedaling impart.