Water leaking from somewhere - floors soaked in back seat!

I will tell that to the mechanic (can’t check it myself). I had asked initially whether it could be coming from moon roof - and he said there would be water marks on the inside ceiling or on “walls” of the car - but I will tell him about this reply.
Someone else said it could be “vapor lock” problem inside the doors.
Have you heard of that problem with this symptom?