Exhaust problem

The silencer box gets full of condensation and drips from the seams whist the engine is ticking over when cold and after running for a while when the engine is off it drips, been told by the main dealer this is normal for a euro 5+ I think I could be getting fobbed off as I asked for it to be replaced under warranty. I am fairly sure exhaust gases and moisture should only exhaust from the tail pipe. Anyone else had this problem? What can be done about it as it runs out of warranty soon.