Occassionaly if the Source Four XT was installed on a very humid or rainy day condensation can develop inside the fixture under normal operating conditions. The condesation is the result of the installation process not from water intrusion during normal operation.
In order to remove the condensation run the fixture without the lens cover on for a period of time on a low humidity day. Throughly dry the lens cover with a lint free cloth. After both the lens cover and fixture assembly have throughly dried you may reassemble the fixture.