Water leak in the exhaust system

My new to me 98 SN has what I believe to be fiberglass going from the exhaust manifold down to the bilge and into the muffler?
I noticed a funny pattern on these pipes when I looked at the boat but assumed it was something to do with the covering used Today after skiing I opened the engine cover and the thought struck me that the pattern looked different between the two sides and looks like water stains.
Sure enough I fired up the engine and there are little droplets of water forming on the outside of the pipes and eventually running down into the bilge.
So my big question. Is this normal? Or does this happen after a period of time and they should be replaced????? Or some inventive additional cooling system developed for my boat ?????    

My ‘89s invertalow had a slight crack/leak as well on the starboard side. I was able to repair mine. I bet you can fix yours if you re-glass it.

I see I never updated this post with my resolution. The follwoing spring I took out the fiberglass down pipes to repair them for the seepage. They were toast. Mushy on the ends and lots of fiberglass matting and strands hanging inside of them. I suspect the a PO maybe overheated  it at one time. Replaced all the hoses too. The hosees came off fairly easy with some heat from a hair drier and little prying. I removed the doghouse and flooring to make things more accessible. I dont have a picture of the tubes but still have them somewhere and could ge ta pic if need be.