Check window seals,,,weep holes,,,,termination bars @ slide roof& slide walls,,,slide floor termination ( make sure slide floor edge is protected & sealed,,,slide frame screws at slide side & back walls,,,
Added thought: check roof wall gutters where gutter May drip down slide wall near window,,,may have compromised exterior window sealant issue. Also,on a previous TT long ago,,,one of our window weep holes got plugged & cause condensation to periodically drip inside with moisture that coun’t escape,,,,about drove us nuts,,,,good luck 🍀👍🌞