I had an A/C leaking problem as well, when it was raining. My A/C was set on auto and the fan was running on low when the leaking started. The problem seemed to stop occurring by switching the fan to high. I found some info in the Atwood A/C owner manual about condensation in high humidity, might be helpful.
In areas of high humidity, the humid air within the RV will cause "sweating" or condensation in parts of the unit as the humid warm air contacts the colder air discharge system. If this occurs please ensure the following:
-Closing all doors, hatches, windows and blinds to limit the ingress of warm humid air
- Avoid running the inside fan on LOW or AUTO in such
conditions. Running the fan on HI fan speed will result in higher airflow and reduce the tendency to have condensation form.