Has anyone experienced (or know of someone who has) a separation of the hull and deck at the rub rail, toward the stern, for a 2017 or 2018 310 SLX resulting in leaks?
I had that issue on my 2006 270AJ last year. A number of the screws holding the hull/deck joint started to back out leaving a big gap especially on the starboard side amidships where daylight was lighting up the inside of the hull. Sea Ray also used very little sealant in the join; barely enough to seal and certainly not enough for any kind of structural bond.
I ended up pulling the rub rail, removing the screws, and sealing the joint all the way around the boat with 5200.
I had no grounds to complain to Sea Ray on an 11 year old boat, but as Bt Doctur said at 2017 model should be under warranty.
Back in the '06-ish era there were some issues with that. As B pointed out, the problem was the lack of goop glueing the hull to the deck. Most of those were fixed under good will. I haven't really heard of it being a problem since, but of course that's not to say it can't happen. As mentioned, talk to your dealer. It will be covered under warranty if it is, indeed, an issue.