I have come across this exact problem were I am the host and my friend fails to see items these include items he places, trees he cuts, ships are just a black void with anchors and ladders me turning into a floating head to him.
What seems to “fix” this problem is for the host to go to an completly diffent island but whats the point of multiplayer if you cant play together? The other bugs are somewhat oke to deal with but playtesting this game becomes alot less attractive when your buddy and you cant play together.