When I had my Westsail 32, I have gotten water in the cylinder two different ways.
When the boat
heeled way over in big seas, I have had seas go up the exhaust loop and fill up the muffler
I have also had failure of the antisiphon valve at anchor
, and had water siphon on the intake side and fill up the muffler, exhaust elbow
and get into the cylinders with open exhaust valves.
You have to get to know your yacht and take measures appropriate for your vessel.