Whenever me or my friend gets out of a boat, it seems to disappear. Earlier today, I had my horse in the boat with me, and noticed that it disappeared, along with my horse. After standing and looking at the water for a bit, I began to notice that my horse was shifting between the point that I left and my destination incredibly quickly (seen below). The boat does not seem to be visible underneath the horse. The videos were taken while RTX was active, but it is not a bug regarding RTX, because my friend who doesn't run RTX has the same issue. If you interact with where the boat would be, you also shift between the two locations, but you cannot move the boat, and the only way to stop it is dismounting. The issue can be fixed by moving outside of the simulation distance, or reloading the entire world.