Wurt Merm Tool Falling into Water

I build their houses right beside the ocean or whatever area where sometimes you can build boats, (the issue for me is the spot is too small to make a boat for retrieving items)

and after a night while they are just wandering around their home or I go away for a bit without them they drop their items in the water I'm not sure if it is them reloading in and the items not being equipped also loading in separately near the house

the screenshot below shows a spear from where the house and Merm were before I had to kill him and destroy his home if I tried to retrieve the weapon or in the original case the armour the Merm guard was wearing I could not reach it to give it to him and he'd be in a state of perpetually running toward the equipment trying to reequip himself with it and he would refuse to follow me or ignore it even though he could never get it