Hi all, I have a pair of stainless marine gen3 for 6 years now and I’m very happy with , last week put my boat in the water for the summer season and discovered that have a water leak just from up the water inlet in the manifolds.
how come one manifold is corroded to the point that leaks from a hole and the other manifold is perfect like new condition?
Anyone had any issue like me ?

Water flow to the manifolds is never equal. I’m betting your corroded manifold was damaged/not treated right on the inside. Only way to find out is with a bore scope and examine the inside.