Went up on roof as we hear a drip when raining
 

The through the roof sewer vent pipes are lead. .

really? is that code here in FL?

Call the county building Department and ask them, then if this is not code, call home warranty and have a discussion with them. I have NOT been up on the roof to inspect ours, but the INTERIOR piping all appear to be PVC, but the external piping is grey so it is possible the last few inches are lead for weather resistance.

Not exactly. There is a lead liner (think of it as flashing) that goes over the PVC vent pipes and under the shingles and is bent downward inside the pipe. If you get a new roof, they will replace it with a "plastic" liner of the appropriate color.

Found one at Sparrs building and farm supply. Its a lead flashing with a pipe so its all one piece. Makes sense for flashing, but the connection over the pvc pipe must be good, otherwise any rain coming into the pipe will just drip onto my recessed can light in the bathroom, drip, drip, drip.

FL is different than the rest of the country, that is for sure