I had water coming out of window air conditioner vent after rain? Any fix for this?

I just installed a new window AC this weekend. It is properly tilted out of the window for drainage. Last night we had a minld thunderstorm. When the AC kicked on in "energy mode", water started spraying out of the top vents. Not a lot, but enough to be concerned. When the fan kicked in, you could actually hear the water spray on the inside of the unit. Should I be concerned? Not sure if I should take it back since its only 3 days old.