If you have a look at (third from bottem)
http://forum.mikrotik.com/t/new-hardware-wireless-wire-nray-60-ghz/139765/1
You see the damage water can do, i know this with years of putting antennas up!
If you look at the pictures supplied by Mikrotik the seal is not level with the outside of the plastic gland, this will allow water to sit and it will get in.
