Is this normal with TG-1 (or any underwater camera)

Sometime during a boat trip, I noticed condensation under the lens glass [not the lens, just the glass cover to the lens in the camera housing]. I held the camera in the sun for a few minutes and the condensation disappeared. Photos are fine other than the ones I took before i noticed the condensation. Is this normal or do you think the camera is not water tight? The camera had not been underwater since purchase.