Broken Yanmar engine mount
I had the exact same problem with broken engine mounts on Lagoon 410 S2 catamaran with approx. 500 engine hours, factory installation. It has two Yanmar 3jh4e engines with sd50 saildrives and two mounts on both engines + one mount on saildrive, so the engines are supported on 3 points only. So the two mounts of both engines broke at exact same place on the studs, leading to a broken and severely leaking saildrive double seal on SB engine due to twisting. The Yanmar service at Gran Canaria is a joke so in the end I had to have the studs welded back together and stuff a part of water hose to the saildrive seal to make the leak smaller and sail back to Estonia like that.
I also remember reading about someone else having the same mounts breaking.