Yes, restricting airflow too much can damage your Advent A/C by causing coil freeze-up or compressor strain. The dividing wall is removed to eliminate air turbulence and improve ducted airflow distribution.
Your RV AC is likely experiencing reduced efficiency due to dirty air filters, blocked return air vents, or thermal cycling issues. The system may be short cycling in moderate temperatures, preventing proper dehumidification and cooling.
Coleman Mach AC uses gravity drainage through base weep holes - no pump or tubing. Dripping likely from closed vents disrupting airflow, gasket seal deterioration, or blocked drain path. Try running with vents open first.