Low fan speed, dirty return air filter, high humidity etc can cause Icing up of EVap coil and/or excessive amounts of condensation.
Drip pan under EVA Coil has drain holes that allow for condensation run off.
If not FULLY clear condensation can accumulate faster then drains can remove it.
Then it can drip out of ceiling grill and/or get carried over by fan blower into discharge plenum///leak form ceiling grill or roof duct
High Fan speed, clean return filter, drip pan DRAINS free and clear.
And 'tilt' rig so condensation can NOT run towards roof opening.