re: Mold in closets, (high efficiency air conditioner related)

Does your new unit run a little bit or a lot? It could either be oversized or undersized. When your unit is running, it is dehumidifying. If your unit only runs a little bit, it is dropping the temperature quickly and gets to thermostat set point quickly and shuts off. When it’s not running, moisture is seeping in and not being removed.
Similar situation if it’s undersized except that it’s just not removing enough moisture when the unit is running.