Hi riesyplayz, welcome to the forums,
Thank you for taking the time to share your account of the same incident in the world you host. Unfortunately I do not have much in the way of workarounds to suggest beyond what you have already tried. If you have not tried it already between gameplay sessions it may be worth trying to clear the cache of the console by shutting down and unplugging your system for 2 minutes before rebooting.
As this was the life raft that disappeared during a multiplayer game, I have made a unique report for the team so they can investigate. Should the team suggest any other workarounds I shall update this thread.
If you still have a copy of the save where the raft paddle is floating, would you be willing to share a copy of it? It may help provide the team with clues as to why this issue occurred.
If this is possible, the instructions to do so are here: [Save File Request]
Please note that the team cannot fix and return individual files, but they would use your file to investigate the cause of the issue and hopefully release a fix for the community as a whole.