For hydra lock to be an issue for this engine one would need to turn it over using an electric starter when experiencing a flooded cylinder. Now if you pull the engine though before hand, making sure your engine is working properly you won't/ can't have hydra lock.
So clearly it is fuel related because there are no reports of #1 cylinder failing.
Repeated pre-detonation over time stressing the marginal cylinder strength? Just looking at possible issues here. Not trying to say that's the real cause.
I will use higher octane fuel just to be sure. Can't hurt.