Whisper quiet ductwork problem...need info

Hi all. Trying to figure out an issue with front AC unit...freeze-ups and leak into the bedroom. Dometic mobile tech finds nothing wrong with unit and Dometic suggesting leak of intake and exhaust into plenum causing issues. In looking up into the ductwork, there is a three sided duct that sits on top of the ceiling panel...a c channel ductwork.

The ceiling panel is not insulated, and there is no caulking or tape sealing the c channel ductwork to the ceiling, allowing lots of leakage from the ducts.

That said, could anyone with the whisper quiet system please peek up into their ducts and see if they have more up there than I have! Can be done by removing louvers and feeling or peering in...

Thanks...also found that the front intake and exhaust as well as the rear intake and exhaust (front and back sets of vents) were effectively blocked by foam inserts that should have been blocking the ends of the duct. So far, moving those blocks has resulted in no freeze-ups tonight...first time system has run for 3 hours without freezing. I think this may have been my issue, (lack of proper airflow) but still curious about whether others ductwork is sealed to prevent leakage into roof space.

Thanks..
Celt

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